From 684228e371e7cd71dd6839c733cd00994eb0a318 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 11:32:39 -0800
Subject: [PATCH 1/6] config/lang: add math operations for ints

---
 config/lang/ast/arithmetic.go    |  43 ++++++++++
 config/lang/ast/arithmetic_op.go |  12 +++
 config/lang/check_types.go       |  50 ++++++++++-
 config/lang/eval.go              |  65 +++++++++++++++
 config/lang/eval_test.go         |  32 +++++++
 config/lang/lang.y               |  29 ++++++-
 config/lang/lex.go               |  12 +++
 config/lang/lex_test.go          |   9 ++
 config/lang/parse_test.go        |  31 +++++++
 config/lang/y.go                 |  93 +++++++++++++--------
 config/lang/y.output             | 138 ++++++++++++++++++-------------
 11 files changed, 421 insertions(+), 93 deletions(-)
 create mode 100644 config/lang/ast/arithmetic.go
 create mode 100644 config/lang/ast/arithmetic_op.go

diff --git a/config/lang/ast/arithmetic.go b/config/lang/ast/arithmetic.go
new file mode 100644
index 000000000..94dc24f89
--- /dev/null
+++ b/config/lang/ast/arithmetic.go
@@ -0,0 +1,43 @@
+package ast
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// Arithmetic represents a node where the result is arithmetic of
+// two or more operands in the order given.
+type Arithmetic struct {
+	Op    ArithmeticOp
+	Exprs []Node
+	Posx  Pos
+}
+
+func (n *Arithmetic) Accept(v Visitor) Node {
+	for i, expr := range n.Exprs {
+		n.Exprs[i] = expr.Accept(v)
+	}
+
+	return v(n)
+}
+
+func (n *Arithmetic) Pos() Pos {
+	return n.Posx
+}
+
+func (n *Arithmetic) GoString() string {
+	return fmt.Sprintf("*%#v", *n)
+}
+
+func (n *Arithmetic) String() string {
+	var b bytes.Buffer
+	for _, expr := range n.Exprs {
+		b.WriteString(fmt.Sprintf("%s", expr))
+	}
+
+	return b.String()
+}
+
+func (n *Arithmetic) Type(Scope) (Type, error) {
+	return TypeInt, nil
+}
diff --git a/config/lang/ast/arithmetic_op.go b/config/lang/ast/arithmetic_op.go
new file mode 100644
index 000000000..920b1d56e
--- /dev/null
+++ b/config/lang/ast/arithmetic_op.go
@@ -0,0 +1,12 @@
+package ast
+
+// ArithmeticOp is the operation to use for the math.
+type ArithmeticOp int
+
+const (
+	ArithmeticOpInvalid ArithmeticOp = 0
+	ArithmeticOpAdd     ArithmeticOp = iota
+	ArithmeticOpSub
+	ArithmeticOpMul
+	ArithmeticOpDiv
+)
diff --git a/config/lang/check_types.go b/config/lang/check_types.go
index 0165eadfc..c153055de 100644
--- a/config/lang/check_types.go
+++ b/config/lang/check_types.go
@@ -55,6 +55,9 @@ func (v *TypeCheck) visit(raw ast.Node) ast.Node {
 	var result ast.Node
 	var err error
 	switch n := raw.(type) {
+	case *ast.Arithmetic:
+		tc := &typeCheckArithmetic{n}
+		result, err = tc.TypeCheck(v)
 	case *ast.Call:
 		tc := &typeCheckCall{n}
 		result, err = tc.TypeCheck(v)
@@ -70,7 +73,7 @@ func (v *TypeCheck) visit(raw ast.Node) ast.Node {
 	default:
 		tc, ok := raw.(TypeCheckNode)
 		if !ok {
-			err = fmt.Errorf("unknown node: %#v", raw)
+			err = fmt.Errorf("unknown node for type check: %#v", raw)
 			break
 		}
 
@@ -86,6 +89,51 @@ func (v *TypeCheck) visit(raw ast.Node) ast.Node {
 	return result
 }
 
+type typeCheckArithmetic struct {
+	n *ast.Arithmetic
+}
+
+func (tc *typeCheckArithmetic) TypeCheck(v *TypeCheck) (ast.Node, error) {
+	// The arguments are on the stack in reverse order, so pop them off.
+	args := make([]ast.Type, len(tc.n.Exprs))
+	for i, _ := range tc.n.Exprs {
+		args[len(tc.n.Exprs)-1-i] = v.StackPop()
+	}
+
+	// Determine the resulting type we want
+	mathType := ast.TypeInt
+	switch v := args[0]; v {
+	case ast.TypeInt:
+		fallthrough
+	case ast.TypeFloat:
+		mathType = v
+	default:
+		return nil, fmt.Errorf(
+			"Math operations can only be done with ints and floats, got %s",
+			v)
+	}
+
+	// Verify the args
+	for i, arg := range args {
+		if arg != mathType {
+			cn := v.ImplicitConversion(args[i], mathType, tc.n.Exprs[i])
+			if cn != nil {
+				tc.n.Exprs[i] = cn
+				continue
+			}
+
+			return nil, fmt.Errorf(
+				"operand %d should be %s, got %s",
+				i+1, mathType, arg)
+		}
+	}
+
+	// Return type
+	v.StackPush(mathType)
+
+	return tc.n, nil
+}
+
 type typeCheckCall struct {
 	n *ast.Call
 }
diff --git a/config/lang/eval.go b/config/lang/eval.go
index cc4d756df..d66563c27 100644
--- a/config/lang/eval.go
+++ b/config/lang/eval.go
@@ -134,6 +134,8 @@ func (v *evalVisitor) visit(raw ast.Node) ast.Node {
 // types as well as any other EvalNode implementations.
 func evalNode(raw ast.Node) (EvalNode, error) {
 	switch n := raw.(type) {
+	case *ast.Arithmetic:
+		return &evalArithmetic{n}, nil
 	case *ast.Call:
 		return &evalCall{n}, nil
 	case *ast.Concat:
@@ -152,6 +154,69 @@ func evalNode(raw ast.Node) (EvalNode, error) {
 	}
 }
 
+type evalArithmetic struct{ *ast.Arithmetic }
+
+func (v *evalArithmetic) Eval(
+	s ast.Scope, stack *ast.Stack) (interface{}, ast.Type, error) {
+	// The arguments are on the stack in reverse order, so pop them off.
+	var resultType ast.Type
+	exprs := make([]interface{}, len(v.Exprs))
+	for i, _ := range v.Exprs {
+		node := stack.Pop().(*ast.LiteralNode)
+		exprs[len(v.Exprs)-1-i] = node.Value
+		resultType = node.Typex
+	}
+
+	// Do the operation
+	var result interface{}
+	var err error
+	switch resultType {
+	case ast.TypeInt:
+		result, err = v.evalInt(v.Op, exprs)
+	default:
+		return nil, resultType, fmt.Errorf(
+			"unknown math operand type: %s", resultType)
+	}
+
+	return result, resultType, err
+}
+
+func (v *evalArithmetic) evalInt(
+	op ast.ArithmeticOp, exprs []interface{}) (int, error) {
+	switch v.Op {
+	case ast.ArithmeticOpAdd:
+		result := 0
+		for _, expr := range exprs {
+			result += expr.(int)
+		}
+
+		return result, nil
+	case ast.ArithmeticOpSub:
+		result := exprs[0].(int)
+		for _, expr := range exprs[1:] {
+			result -= expr.(int)
+		}
+
+		return result, nil
+	case ast.ArithmeticOpMul:
+		result := exprs[0].(int)
+		for _, expr := range exprs[1:] {
+			result *= expr.(int)
+		}
+
+		return result, nil
+	case ast.ArithmeticOpDiv:
+		result := exprs[0].(int)
+		for _, expr := range exprs[1:] {
+			result /= expr.(int)
+		}
+
+		return result, nil
+	default:
+		return 0, fmt.Errorf("unknown math operation: %s", v.Op)
+	}
+}
+
 type evalCall struct{ *ast.Call }
 
 func (v *evalCall) Eval(s ast.Scope, stack *ast.Stack) (interface{}, ast.Type, error) {
diff --git a/config/lang/eval_test.go b/config/lang/eval_test.go
index bf66be79f..e0c53db83 100644
--- a/config/lang/eval_test.go
+++ b/config/lang/eval_test.go
@@ -39,6 +39,38 @@ func TestEval(t *testing.T) {
 			ast.TypeString,
 		},
 
+		{
+			"foo ${42+1}",
+			nil,
+			false,
+			"foo 43",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42-1}",
+			nil,
+			false,
+			"foo 41",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42*2}",
+			nil,
+			false,
+			"foo 84",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42/2}",
+			nil,
+			false,
+			"foo 21",
+			ast.TypeString,
+		},
+
 		{
 			"foo ${rand()}",
 			&ast.BasicScope{
diff --git a/config/lang/lang.y b/config/lang/lang.y
index 4ee47fb54..68c7d0b37 100644
--- a/config/lang/lang.y
+++ b/config/lang/lang.y
@@ -22,9 +22,9 @@ import (
 %token  <str> PROGRAM_STRING_START PROGRAM_STRING_END
 %token  <str> PAREN_LEFT PAREN_RIGHT COMMA
 
-%token <token> IDENTIFIER INTEGER FLOAT STRING
+%token <token> ARITH_OP IDENTIFIER INTEGER FLOAT STRING
 
-%type <node> expr interpolation literal literalModeTop literalModeValue
+%type <node> arith expr interpolation literal literalModeTop literalModeValue
 %type <nodeList> args
 
 %%
@@ -116,6 +116,10 @@ expr:
             Posx:  $1.Pos,
         }
     }
+|   arith
+    {
+        $$ = $1
+    }
 |   IDENTIFIER
     {
         $$ = &ast.VariableAccess{Name: $1.Value.(string), Posx: $1.Pos}
@@ -125,6 +129,27 @@ expr:
         $$ = &ast.Call{Func: $1.Value.(string), Args: $3, Posx: $1.Pos}
     }
 
+arith:
+    INTEGER ARITH_OP INTEGER
+    {
+        $$ = &ast.Arithmetic{
+            Op:    $2.Value.(ast.ArithmeticOp),
+            Exprs: []ast.Node{
+                &ast.LiteralNode{
+                    Value:  $1.Value.(int),
+                    Typex:  ast.TypeInt,
+                    Posx:   $1.Pos,
+                },
+                &ast.LiteralNode{
+                    Value:  $3.Value.(int),
+                    Typex:  ast.TypeInt,
+                    Posx:   $3.Pos,
+                },
+            },
+            Posx: $1.Pos,
+        }
+    }
+
 args:
 	{
 		$$ = nil
diff --git a/config/lang/lex.go b/config/lang/lex.go
index a1172b420..6b30f2a4c 100644
--- a/config/lang/lex.go
+++ b/config/lang/lex.go
@@ -168,6 +168,18 @@ func (x *parserLex) lexModeInterpolation(yylval *parserSymType) int {
 			return PAREN_RIGHT
 		case ',':
 			return COMMA
+		case '+':
+			yylval.token = &parserToken{Value: ast.ArithmeticOpAdd}
+			return ARITH_OP
+		case '-':
+			yylval.token = &parserToken{Value: ast.ArithmeticOpSub}
+			return ARITH_OP
+		case '*':
+			yylval.token = &parserToken{Value: ast.ArithmeticOpMul}
+			return ARITH_OP
+		case '/':
+			yylval.token = &parserToken{Value: ast.ArithmeticOpDiv}
+			return ARITH_OP
 		default:
 			x.backup()
 			return x.lexId(yylval)
diff --git a/config/lang/lex_test.go b/config/lang/lex_test.go
index 8c5207d78..5341e594a 100644
--- a/config/lang/lex_test.go
+++ b/config/lang/lex_test.go
@@ -63,6 +63,15 @@ func TestLex(t *testing.T) {
 				PROGRAM_BRACKET_RIGHT, lexEOF},
 		},
 
+		{
+			"${bar(42+1)}",
+			[]int{PROGRAM_BRACKET_LEFT,
+				IDENTIFIER, PAREN_LEFT,
+				INTEGER, ARITH_OP, INTEGER,
+				PAREN_RIGHT,
+				PROGRAM_BRACKET_RIGHT, lexEOF},
+		},
+
 		{
 			"${bar(3.14159)}",
 			[]int{PROGRAM_BRACKET_LEFT,
diff --git a/config/lang/parse_test.go b/config/lang/parse_test.go
index e2ba2b310..d2671e233 100644
--- a/config/lang/parse_test.go
+++ b/config/lang/parse_test.go
@@ -152,6 +152,37 @@ func TestParse(t *testing.T) {
 			},
 		},
 
+		{
+			"foo ${42+1}",
+			false,
+			&ast.Concat{
+				Posx: ast.Pos{Column: 1, Line: 1},
+				Exprs: []ast.Node{
+					&ast.LiteralNode{
+						Value: "foo ",
+						Typex: ast.TypeString,
+						Posx:  ast.Pos{Column: 1, Line: 1},
+					},
+					&ast.Arithmetic{
+						Op: ast.ArithmeticOpAdd,
+						Exprs: []ast.Node{
+							&ast.LiteralNode{
+								Value: 42,
+								Typex: ast.TypeInt,
+								Posx:  ast.Pos{Column: 7, Line: 1},
+							},
+							&ast.LiteralNode{
+								Value: 1,
+								Typex: ast.TypeInt,
+								Posx:  ast.Pos{Column: 10, Line: 1},
+							},
+						},
+						Posx: ast.Pos{Column: 7, Line: 1},
+					},
+				},
+			},
+		},
+
 		{
 			"${foo()}",
 			false,
diff --git a/config/lang/y.go b/config/lang/y.go
index de1ce7501..bb56ebdc0 100644
--- a/config/lang/y.go
+++ b/config/lang/y.go
@@ -24,10 +24,11 @@ const PROGRAM_STRING_END = 57349
 const PAREN_LEFT = 57350
 const PAREN_RIGHT = 57351
 const COMMA = 57352
-const IDENTIFIER = 57353
-const INTEGER = 57354
-const FLOAT = 57355
-const STRING = 57356
+const ARITH_OP = 57353
+const IDENTIFIER = 57354
+const INTEGER = 57355
+const FLOAT = 57356
+const STRING = 57357
 
 var parserToknames = []string{
 	"PROGRAM_BRACKET_LEFT",
@@ -37,6 +38,7 @@ var parserToknames = []string{
 	"PAREN_LEFT",
 	"PAREN_RIGHT",
 	"COMMA",
+	"ARITH_OP",
 	"IDENTIFIER",
 	"INTEGER",
 	"FLOAT",
@@ -48,7 +50,7 @@ const parserEofCode = 1
 const parserErrCode = 2
 const parserMaxDepth = 200
 
-//line lang.y:151
+//line lang.y:176
 
 //line yacctab:1
 var parserExca = []int{
@@ -57,51 +59,51 @@ var parserExca = []int{
 	-2, 0,
 }
 
-const parserNprod = 17
+const parserNprod = 19
 const parserPrivate = 57344
 
 var parserTokenNames []string
 var parserStates []string
 
-const parserLast = 23
+const parserLast = 26
 
 var parserAct = []int{
 
-	9, 7, 7, 3, 18, 19, 8, 15, 13, 11,
-	12, 6, 6, 14, 8, 1, 17, 10, 2, 16,
-	20, 4, 5,
+	9, 7, 7, 18, 3, 21, 22, 8, 17, 14,
+	11, 12, 6, 6, 16, 8, 15, 1, 20, 10,
+	2, 19, 4, 23, 5, 13,
 }
 var parserPact = []int{
 
-	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 8,
-	-2, -1000, -1000, -1, -1000, -3, -5, -1000, -1000, -3,
-	-1000,
+	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 11,
+	-2, 3, -1000, -1000, 0, -1000, -10, -3, -1000, -4,
+	-1000, -1000, -3, -1000,
 }
 var parserPgo = []int{
 
-	0, 0, 22, 21, 17, 3, 19, 15,
+	0, 25, 0, 24, 22, 19, 4, 21, 17,
 }
 var parserR1 = []int{
 
-	0, 7, 7, 4, 4, 5, 5, 2, 1, 1,
-	1, 1, 1, 6, 6, 6, 3,
+	0, 8, 8, 5, 5, 6, 6, 3, 2, 2,
+	2, 2, 2, 2, 1, 7, 7, 7, 4,
 }
 var parserR2 = []int{
 
 	0, 0, 1, 1, 2, 1, 1, 3, 1, 1,
-	1, 1, 4, 0, 3, 1, 1,
+	1, 1, 1, 4, 3, 0, 3, 1, 1,
 }
 var parserChk = []int{
 
-	-1000, -7, -4, -5, -3, -2, 14, 4, -5, -1,
-	-4, 12, 13, 11, 5, 8, -6, -1, 9, 10,
-	-1,
+	-1000, -8, -5, -6, -4, -3, 15, 4, -6, -2,
+	-5, 13, 14, -1, 12, 5, 11, 8, 13, -7,
+	-2, 9, 10, -2,
 }
 var parserDef = []int{
 
-	1, -2, 2, 3, 5, 6, 16, 0, 4, 0,
-	8, 9, 10, 11, 7, 13, 0, 15, 12, 0,
-	14,
+	1, -2, 2, 3, 5, 6, 18, 0, 4, 0,
+	8, 9, 10, 11, 12, 7, 0, 15, 14, 0,
+	17, 13, 0, 16,
 }
 var parserTok1 = []int{
 
@@ -110,7 +112,7 @@ var parserTok1 = []int{
 var parserTok2 = []int{
 
 	2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
-	12, 13, 14,
+	12, 13, 14, 15,
 }
 var parserTok3 = []int{
 	0,
@@ -433,30 +435,55 @@ parserdefault:
 	case 11:
 		//line lang.y:120
 		{
-			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
+			parserVAL.node = parserS[parserpt-0].node
 		}
 	case 12:
 		//line lang.y:124
 		{
-			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
+			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
 		}
 	case 13:
-		//line lang.y:129
+		//line lang.y:128
+		{
+			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
+		}
+	case 14:
+		//line lang.y:134
+		{
+			parserVAL.node = &ast.Arithmetic{
+				Op: parserS[parserpt-1].token.Value.(ast.ArithmeticOp),
+				Exprs: []ast.Node{
+					&ast.LiteralNode{
+						Value: parserS[parserpt-2].token.Value.(int),
+						Typex: ast.TypeInt,
+						Posx:  parserS[parserpt-2].token.Pos,
+					},
+					&ast.LiteralNode{
+						Value: parserS[parserpt-0].token.Value.(int),
+						Typex: ast.TypeInt,
+						Posx:  parserS[parserpt-0].token.Pos,
+					},
+				},
+				Posx: parserS[parserpt-2].token.Pos,
+			}
+		}
+	case 15:
+		//line lang.y:154
 		{
 			parserVAL.nodeList = nil
 		}
-	case 14:
-		//line lang.y:133
+	case 16:
+		//line lang.y:158
 		{
 			parserVAL.nodeList = append(parserS[parserpt-2].nodeList, parserS[parserpt-0].node)
 		}
-	case 15:
-		//line lang.y:137
+	case 17:
+		//line lang.y:162
 		{
 			parserVAL.nodeList = append(parserVAL.nodeList, parserS[parserpt-0].node)
 		}
-	case 16:
-		//line lang.y:143
+	case 18:
+		//line lang.y:168
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(string),
diff --git a/config/lang/y.output b/config/lang/y.output
index aa076e45a..c1f9df4a0 100644
--- a/config/lang/y.output
+++ b/config/lang/y.output
@@ -51,21 +51,22 @@ state 5
 
 
 state 6
-	literal:  STRING.    (16)
+	literal:  STRING.    (18)
 
-	.  reduce 16 (src line 141)
+	.  reduce 18 (src line 166)
 
 
 state 7
 	interpolation:  PROGRAM_BRACKET_LEFT.expr PROGRAM_BRACKET_RIGHT 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
+	IDENTIFIER  shift 14
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
 	.  error
 
+	arith  goto 13
 	expr  goto 9
 	interpolation  goto 5
 	literal  goto 4
@@ -81,7 +82,7 @@ state 8
 state 9
 	interpolation:  PROGRAM_BRACKET_LEFT expr.PROGRAM_BRACKET_RIGHT 
 
-	PROGRAM_BRACKET_RIGHT  shift 14
+	PROGRAM_BRACKET_RIGHT  shift 15
 	.  error
 
 
@@ -99,7 +100,9 @@ state 10
 
 state 11
 	expr:  INTEGER.    (9)
+	arith:  INTEGER.ARITH_OP INTEGER 
 
+	ARITH_OP  shift 16
 	.  reduce 9 (src line 103)
 
 
@@ -110,89 +113,110 @@ state 12
 
 
 state 13
-	expr:  IDENTIFIER.    (11)
-	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
+	expr:  arith.    (11)
 
-	PAREN_LEFT  shift 15
 	.  reduce 11 (src line 119)
 
 
 state 14
+	expr:  IDENTIFIER.    (12)
+	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
+
+	PAREN_LEFT  shift 17
+	.  reduce 12 (src line 123)
+
+
+state 15
 	interpolation:  PROGRAM_BRACKET_LEFT expr PROGRAM_BRACKET_RIGHT.    (7)
 
 	.  reduce 7 (src line 92)
 
 
-state 15
-	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
-	args: .    (13)
-
-	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
-	INTEGER  shift 11
-	FLOAT  shift 12
-	STRING  shift 6
-	.  reduce 13 (src line 128)
-
-	expr  goto 17
-	interpolation  goto 5
-	literal  goto 4
-	literalModeTop  goto 10
-	literalModeValue  goto 3
-	args  goto 16
-
 state 16
-	expr:  IDENTIFIER PAREN_LEFT args.PAREN_RIGHT 
-	args:  args.COMMA expr 
+	arith:  INTEGER ARITH_OP.INTEGER 
 
-	PAREN_RIGHT  shift 18
-	COMMA  shift 19
+	INTEGER  shift 18
 	.  error
 
 
 state 17
-	args:  expr.    (15)
-
-	.  reduce 15 (src line 136)
-
-
-state 18
-	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (12)
-
-	.  reduce 12 (src line 123)
-
-
-state 19
-	args:  args COMMA.expr 
+	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
+	args: .    (15)
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
+	IDENTIFIER  shift 14
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
-	.  error
+	.  reduce 15 (src line 153)
 
+	arith  goto 13
 	expr  goto 20
 	interpolation  goto 5
 	literal  goto 4
 	literalModeTop  goto 10
 	literalModeValue  goto 3
+	args  goto 19
 
-state 20
-	args:  args COMMA expr.    (14)
+state 18
+	arith:  INTEGER ARITH_OP INTEGER.    (14)
 
 	.  reduce 14 (src line 132)
 
 
-14 terminals, 8 nonterminals
-17 grammar rules, 21/2000 states
+state 19
+	expr:  IDENTIFIER PAREN_LEFT args.PAREN_RIGHT 
+	args:  args.COMMA expr 
+
+	PAREN_RIGHT  shift 21
+	COMMA  shift 22
+	.  error
+
+
+state 20
+	args:  expr.    (17)
+
+	.  reduce 17 (src line 161)
+
+
+state 21
+	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (13)
+
+	.  reduce 13 (src line 127)
+
+
+state 22
+	args:  args COMMA.expr 
+
+	PROGRAM_BRACKET_LEFT  shift 7
+	IDENTIFIER  shift 14
+	INTEGER  shift 11
+	FLOAT  shift 12
+	STRING  shift 6
+	.  error
+
+	arith  goto 13
+	expr  goto 23
+	interpolation  goto 5
+	literal  goto 4
+	literalModeTop  goto 10
+	literalModeValue  goto 3
+
+state 23
+	args:  args COMMA expr.    (16)
+
+	.  reduce 16 (src line 157)
+
+
+15 terminals, 9 nonterminals
+19 grammar rules, 24/2000 states
 0 shift/reduce, 0 reduce/reduce conflicts reported
-57 working sets used
-memory: parser 25/30000
-16 extra closures
-25 shift entries, 1 exceptions
-12 goto entries
-15 entries saved by goto default
-Optimizer space used: output 23/30000
-23 table entries, 0 zero
-maximum spread: 14, maximum offset: 19
+58 working sets used
+memory: parser 28/30000
+19 extra closures
+27 shift entries, 1 exceptions
+13 goto entries
+17 entries saved by goto default
+Optimizer space used: output 26/30000
+26 table entries, 0 zero
+maximum spread: 15, maximum offset: 22

From 07b78fdf84a6537b63202790871aefadadd50395 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 14:26:14 -0800
Subject: [PATCH 2/6] config/lang: math operations

---
 config/lang/builtins.go    |  96 ++++++++++++++++++++++++++
 config/lang/check_types.go |  30 +++++++--
 config/lang/eval.go        |  73 ++------------------
 config/lang/eval_test.go   |  24 +++++++
 config/lang/lang.y         |  31 ++-------
 config/lang/y.go           |  80 +++++++++-------------
 config/lang/y.output       | 133 +++++++++++++++++++------------------
 7 files changed, 259 insertions(+), 208 deletions(-)

diff --git a/config/lang/builtins.go b/config/lang/builtins.go
index e8513119f..e14aba0d8 100644
--- a/config/lang/builtins.go
+++ b/config/lang/builtins.go
@@ -15,11 +15,107 @@ func registerBuiltins(scope *ast.BasicScope) *ast.BasicScope {
 	if scope.FuncMap == nil {
 		scope.FuncMap = make(map[string]ast.Function)
 	}
+
+	// Implicit conversions
+	scope.FuncMap["__builtin_FloatToInt"] = builtinFloatToInt()
+	scope.FuncMap["__builtin_FloatToString"] = builtinFloatToString()
+	scope.FuncMap["__builtin_IntToFloat"] = builtinIntToFloat()
 	scope.FuncMap["__builtin_IntToString"] = builtinIntToString()
 	scope.FuncMap["__builtin_StringToInt"] = builtinStringToInt()
+
+	// Math operations
+	scope.FuncMap["__builtin_IntMath"] = builtinIntMath()
+	scope.FuncMap["__builtin_FloatMath"] = builtinFloatMath()
 	return scope
 }
 
+func builtinFloatMath() ast.Function {
+	return ast.Function{
+		ArgTypes:     []ast.Type{ast.TypeInt},
+		Variadic:     true,
+		VariadicType: ast.TypeFloat,
+		ReturnType:   ast.TypeFloat,
+		Callback: func(args []interface{}) (interface{}, error) {
+			op := args[0].(ast.ArithmeticOp)
+			result := args[1].(float64)
+			for _, raw := range args[2:] {
+				arg := raw.(float64)
+				switch op {
+				case ast.ArithmeticOpAdd:
+					result += arg
+				case ast.ArithmeticOpSub:
+					result -= arg
+				case ast.ArithmeticOpMul:
+					result *= arg
+				case ast.ArithmeticOpDiv:
+					result /= arg
+				}
+			}
+
+			return result, nil
+		},
+	}
+}
+
+func builtinIntMath() ast.Function {
+	return ast.Function{
+		ArgTypes:     []ast.Type{ast.TypeInt},
+		Variadic:     true,
+		VariadicType: ast.TypeInt,
+		ReturnType:   ast.TypeInt,
+		Callback: func(args []interface{}) (interface{}, error) {
+			op := args[0].(ast.ArithmeticOp)
+			result := args[1].(int)
+			for _, raw := range args[2:] {
+				arg := raw.(int)
+				switch op {
+				case ast.ArithmeticOpAdd:
+					result += arg
+				case ast.ArithmeticOpSub:
+					result -= arg
+				case ast.ArithmeticOpMul:
+					result *= arg
+				case ast.ArithmeticOpDiv:
+					result /= arg
+				}
+			}
+
+			return result, nil
+		},
+	}
+}
+
+func builtinFloatToInt() ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeFloat},
+		ReturnType: ast.TypeInt,
+		Callback: func(args []interface{}) (interface{}, error) {
+			return int(args[0].(float64)), nil
+		},
+	}
+}
+
+func builtinFloatToString() ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeFloat},
+		ReturnType: ast.TypeString,
+		Callback: func(args []interface{}) (interface{}, error) {
+			return strconv.FormatFloat(
+				args[0].(float64), 'g', -1, 64), nil
+		},
+	}
+}
+
+func builtinIntToFloat() ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeInt},
+		ReturnType: ast.TypeFloat,
+		Callback: func(args []interface{}) (interface{}, error) {
+			return float64(args[0].(int)), nil
+		},
+	}
+}
+
 func builtinIntToString() ast.Function {
 	return ast.Function{
 		ArgTypes:   []ast.Type{ast.TypeInt},
diff --git a/config/lang/check_types.go b/config/lang/check_types.go
index c153055de..3b6eefbf0 100644
--- a/config/lang/check_types.go
+++ b/config/lang/check_types.go
@@ -95,17 +95,20 @@ type typeCheckArithmetic struct {
 
 func (tc *typeCheckArithmetic) TypeCheck(v *TypeCheck) (ast.Node, error) {
 	// The arguments are on the stack in reverse order, so pop them off.
-	args := make([]ast.Type, len(tc.n.Exprs))
+	exprs := make([]ast.Type, len(tc.n.Exprs))
 	for i, _ := range tc.n.Exprs {
-		args[len(tc.n.Exprs)-1-i] = v.StackPop()
+		exprs[len(tc.n.Exprs)-1-i] = v.StackPop()
 	}
 
 	// Determine the resulting type we want
+	mathFunc := "__builtin_IntMath"
 	mathType := ast.TypeInt
-	switch v := args[0]; v {
+	switch v := exprs[0]; v {
 	case ast.TypeInt:
-		fallthrough
+		mathFunc = "__builtin_IntMath"
+		mathType = v
 	case ast.TypeFloat:
+		mathFunc = "__builtin_FloatMath"
 		mathType = v
 	default:
 		return nil, fmt.Errorf(
@@ -114,9 +117,9 @@ func (tc *typeCheckArithmetic) TypeCheck(v *TypeCheck) (ast.Node, error) {
 	}
 
 	// Verify the args
-	for i, arg := range args {
+	for i, arg := range exprs {
 		if arg != mathType {
-			cn := v.ImplicitConversion(args[i], mathType, tc.n.Exprs[i])
+			cn := v.ImplicitConversion(exprs[i], mathType, tc.n.Exprs[i])
 			if cn != nil {
 				tc.n.Exprs[i] = cn
 				continue
@@ -131,7 +134,20 @@ func (tc *typeCheckArithmetic) TypeCheck(v *TypeCheck) (ast.Node, error) {
 	// Return type
 	v.StackPush(mathType)
 
-	return tc.n, nil
+	// Replace our node with a call to the proper function. This isn't
+	// type checked but we already verified types.
+	args := make([]ast.Node, len(tc.n.Exprs)+1)
+	args[0] = &ast.LiteralNode{
+		Value: tc.n.Op,
+		Typex: ast.TypeInt,
+		Posx:  tc.n.Pos(),
+	}
+	copy(args[1:], tc.n.Exprs)
+	return &ast.Call{
+		Func: mathFunc,
+		Args: args,
+		Posx: tc.n.Pos(),
+	}, nil
 }
 
 type typeCheckCall struct {
diff --git a/config/lang/eval.go b/config/lang/eval.go
index d66563c27..9ec583e41 100644
--- a/config/lang/eval.go
+++ b/config/lang/eval.go
@@ -32,7 +32,12 @@ func Eval(root ast.Node, config *EvalConfig) (interface{}, ast.Type, error) {
 	}
 	scope := registerBuiltins(config.GlobalScope)
 	implicitMap := map[ast.Type]map[ast.Type]string{
+		ast.TypeFloat: {
+			ast.TypeInt:    "__builtin_FloatToInt",
+			ast.TypeString: "__builtin_FloatToString",
+		},
 		ast.TypeInt: {
+			ast.TypeFloat:  "__builtin_IntToFloat",
 			ast.TypeString: "__builtin_IntToString",
 		},
 		ast.TypeString: {
@@ -47,7 +52,8 @@ func Eval(root ast.Node, config *EvalConfig) (interface{}, ast.Type, error) {
 	// Build up the semantic checks for execution
 	checks := make(
 		[]SemanticChecker,
-		len(config.SemanticChecks), len(config.SemanticChecks)+2)
+		len(config.SemanticChecks),
+		len(config.SemanticChecks)+2)
 	copy(checks, config.SemanticChecks)
 	checks = append(checks, ic.Visit)
 	checks = append(checks, tv.Visit)
@@ -134,8 +140,6 @@ func (v *evalVisitor) visit(raw ast.Node) ast.Node {
 // types as well as any other EvalNode implementations.
 func evalNode(raw ast.Node) (EvalNode, error) {
 	switch n := raw.(type) {
-	case *ast.Arithmetic:
-		return &evalArithmetic{n}, nil
 	case *ast.Call:
 		return &evalCall{n}, nil
 	case *ast.Concat:
@@ -154,69 +158,6 @@ func evalNode(raw ast.Node) (EvalNode, error) {
 	}
 }
 
-type evalArithmetic struct{ *ast.Arithmetic }
-
-func (v *evalArithmetic) Eval(
-	s ast.Scope, stack *ast.Stack) (interface{}, ast.Type, error) {
-	// The arguments are on the stack in reverse order, so pop them off.
-	var resultType ast.Type
-	exprs := make([]interface{}, len(v.Exprs))
-	for i, _ := range v.Exprs {
-		node := stack.Pop().(*ast.LiteralNode)
-		exprs[len(v.Exprs)-1-i] = node.Value
-		resultType = node.Typex
-	}
-
-	// Do the operation
-	var result interface{}
-	var err error
-	switch resultType {
-	case ast.TypeInt:
-		result, err = v.evalInt(v.Op, exprs)
-	default:
-		return nil, resultType, fmt.Errorf(
-			"unknown math operand type: %s", resultType)
-	}
-
-	return result, resultType, err
-}
-
-func (v *evalArithmetic) evalInt(
-	op ast.ArithmeticOp, exprs []interface{}) (int, error) {
-	switch v.Op {
-	case ast.ArithmeticOpAdd:
-		result := 0
-		for _, expr := range exprs {
-			result += expr.(int)
-		}
-
-		return result, nil
-	case ast.ArithmeticOpSub:
-		result := exprs[0].(int)
-		for _, expr := range exprs[1:] {
-			result -= expr.(int)
-		}
-
-		return result, nil
-	case ast.ArithmeticOpMul:
-		result := exprs[0].(int)
-		for _, expr := range exprs[1:] {
-			result *= expr.(int)
-		}
-
-		return result, nil
-	case ast.ArithmeticOpDiv:
-		result := exprs[0].(int)
-		for _, expr := range exprs[1:] {
-			result /= expr.(int)
-		}
-
-		return result, nil
-	default:
-		return 0, fmt.Errorf("unknown math operation: %s", v.Op)
-	}
-}
-
 type evalCall struct{ *ast.Call }
 
 func (v *evalCall) Eval(s ast.Scope, stack *ast.Stack) (interface{}, ast.Type, error) {
diff --git a/config/lang/eval_test.go b/config/lang/eval_test.go
index e0c53db83..3446be9d2 100644
--- a/config/lang/eval_test.go
+++ b/config/lang/eval_test.go
@@ -71,6 +71,30 @@ func TestEval(t *testing.T) {
 			ast.TypeString,
 		},
 
+		{
+			"foo ${42.0+1.0}",
+			nil,
+			false,
+			"foo 43",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42.0+1}",
+			nil,
+			false,
+			"foo 43",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42+1.0}",
+			nil,
+			false,
+			"foo 43",
+			ast.TypeString,
+		},
+
 		{
 			"foo ${rand()}",
 			&ast.BasicScope{
diff --git a/config/lang/lang.y b/config/lang/lang.y
index 68c7d0b37..96517a76e 100644
--- a/config/lang/lang.y
+++ b/config/lang/lang.y
@@ -24,7 +24,7 @@ import (
 
 %token <token> ARITH_OP IDENTIFIER INTEGER FLOAT STRING
 
-%type <node> arith expr interpolation literal literalModeTop literalModeValue
+%type <node> expr interpolation literal literalModeTop literalModeValue
 %type <nodeList> args
 
 %%
@@ -116,9 +116,13 @@ expr:
             Posx:  $1.Pos,
         }
     }
-|   arith
+|   expr ARITH_OP expr
     {
-        $$ = $1
+        $$ = &ast.Arithmetic{
+            Op:    $2.Value.(ast.ArithmeticOp),
+            Exprs: []ast.Node{$1, $3},
+            Posx:  $1.Pos(),
+        }
     }
 |   IDENTIFIER
     {
@@ -129,27 +133,6 @@ expr:
         $$ = &ast.Call{Func: $1.Value.(string), Args: $3, Posx: $1.Pos}
     }
 
-arith:
-    INTEGER ARITH_OP INTEGER
-    {
-        $$ = &ast.Arithmetic{
-            Op:    $2.Value.(ast.ArithmeticOp),
-            Exprs: []ast.Node{
-                &ast.LiteralNode{
-                    Value:  $1.Value.(int),
-                    Typex:  ast.TypeInt,
-                    Posx:   $1.Pos,
-                },
-                &ast.LiteralNode{
-                    Value:  $3.Value.(int),
-                    Typex:  ast.TypeInt,
-                    Posx:   $3.Pos,
-                },
-            },
-            Posx: $1.Pos,
-        }
-    }
-
 args:
 	{
 		$$ = nil
diff --git a/config/lang/y.go b/config/lang/y.go
index bb56ebdc0..f9198d8f7 100644
--- a/config/lang/y.go
+++ b/config/lang/y.go
@@ -50,7 +50,7 @@ const parserEofCode = 1
 const parserErrCode = 2
 const parserMaxDepth = 200
 
-//line lang.y:176
+//line lang.y:159
 
 //line yacctab:1
 var parserExca = []int{
@@ -59,7 +59,7 @@ var parserExca = []int{
 	-2, 0,
 }
 
-const parserNprod = 19
+const parserNprod = 18
 const parserPrivate = 57344
 
 var parserTokenNames []string
@@ -69,41 +69,41 @@ const parserLast = 26
 
 var parserAct = []int{
 
-	9, 7, 7, 18, 3, 21, 22, 8, 17, 14,
-	11, 12, 6, 6, 16, 8, 15, 1, 20, 10,
-	2, 19, 4, 23, 5, 13,
+	9, 7, 7, 15, 3, 20, 21, 8, 14, 13,
+	11, 12, 6, 6, 15, 8, 17, 19, 16, 10,
+	2, 1, 22, 18, 4, 5,
 }
 var parserPact = []int{
 
-	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 11,
-	-2, 3, -1000, -1000, 0, -1000, -10, -3, -1000, -4,
-	-1000, -1000, -3, -1000,
+	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 3,
+	-2, -1000, -1000, 10, -1000, -3, -3, -8, -4, -8,
+	-1000, -3, -8,
 }
 var parserPgo = []int{
 
-	0, 25, 0, 24, 22, 19, 4, 21, 17,
+	0, 0, 25, 24, 19, 4, 23, 21,
 }
 var parserR1 = []int{
 
-	0, 8, 8, 5, 5, 6, 6, 3, 2, 2,
-	2, 2, 2, 2, 1, 7, 7, 7, 4,
+	0, 7, 7, 4, 4, 5, 5, 2, 1, 1,
+	1, 1, 1, 1, 6, 6, 6, 3,
 }
 var parserR2 = []int{
 
 	0, 0, 1, 1, 2, 1, 1, 3, 1, 1,
-	1, 1, 1, 4, 3, 0, 3, 1, 1,
+	1, 3, 1, 4, 0, 3, 1, 1,
 }
 var parserChk = []int{
 
-	-1000, -8, -5, -6, -4, -3, 15, 4, -6, -2,
-	-5, 13, 14, -1, 12, 5, 11, 8, 13, -7,
-	-2, 9, 10, -2,
+	-1000, -7, -4, -5, -3, -2, 15, 4, -5, -1,
+	-4, 13, 14, 12, 5, 11, 8, -1, -6, -1,
+	9, 10, -1,
 }
 var parserDef = []int{
 
-	1, -2, 2, 3, 5, 6, 18, 0, 4, 0,
-	8, 9, 10, 11, 12, 7, 0, 15, 14, 0,
-	17, 13, 0, 16,
+	1, -2, 2, 3, 5, 6, 17, 0, 4, 0,
+	8, 9, 10, 12, 7, 0, 14, 11, 0, 16,
+	13, 0, 15,
 }
 var parserTok1 = []int{
 
@@ -435,55 +435,39 @@ parserdefault:
 	case 11:
 		//line lang.y:120
 		{
-			parserVAL.node = parserS[parserpt-0].node
+			parserVAL.node = &ast.Arithmetic{
+				Op:    parserS[parserpt-1].token.Value.(ast.ArithmeticOp),
+				Exprs: []ast.Node{parserS[parserpt-2].node, parserS[parserpt-0].node},
+				Posx:  parserS[parserpt-2].node.Pos(),
+			}
 		}
 	case 12:
-		//line lang.y:124
+		//line lang.y:128
 		{
 			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
 		}
 	case 13:
-		//line lang.y:128
+		//line lang.y:132
 		{
 			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
 		}
 	case 14:
-		//line lang.y:134
-		{
-			parserVAL.node = &ast.Arithmetic{
-				Op: parserS[parserpt-1].token.Value.(ast.ArithmeticOp),
-				Exprs: []ast.Node{
-					&ast.LiteralNode{
-						Value: parserS[parserpt-2].token.Value.(int),
-						Typex: ast.TypeInt,
-						Posx:  parserS[parserpt-2].token.Pos,
-					},
-					&ast.LiteralNode{
-						Value: parserS[parserpt-0].token.Value.(int),
-						Typex: ast.TypeInt,
-						Posx:  parserS[parserpt-0].token.Pos,
-					},
-				},
-				Posx: parserS[parserpt-2].token.Pos,
-			}
-		}
-	case 15:
-		//line lang.y:154
+		//line lang.y:137
 		{
 			parserVAL.nodeList = nil
 		}
-	case 16:
-		//line lang.y:158
+	case 15:
+		//line lang.y:141
 		{
 			parserVAL.nodeList = append(parserS[parserpt-2].nodeList, parserS[parserpt-0].node)
 		}
-	case 17:
-		//line lang.y:162
+	case 16:
+		//line lang.y:145
 		{
 			parserVAL.nodeList = append(parserVAL.nodeList, parserS[parserpt-0].node)
 		}
-	case 18:
-		//line lang.y:168
+	case 17:
+		//line lang.y:151
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(string),
diff --git a/config/lang/y.output b/config/lang/y.output
index c1f9df4a0..d524d1e2e 100644
--- a/config/lang/y.output
+++ b/config/lang/y.output
@@ -51,22 +51,21 @@ state 5
 
 
 state 6
-	literal:  STRING.    (18)
+	literal:  STRING.    (17)
 
-	.  reduce 18 (src line 166)
+	.  reduce 17 (src line 149)
 
 
 state 7
 	interpolation:  PROGRAM_BRACKET_LEFT.expr PROGRAM_BRACKET_RIGHT 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 14
+	IDENTIFIER  shift 13
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
 	.  error
 
-	arith  goto 13
 	expr  goto 9
 	interpolation  goto 5
 	literal  goto 4
@@ -81,8 +80,10 @@ state 8
 
 state 9
 	interpolation:  PROGRAM_BRACKET_LEFT expr.PROGRAM_BRACKET_RIGHT 
+	expr:  expr.ARITH_OP expr 
 
-	PROGRAM_BRACKET_RIGHT  shift 15
+	PROGRAM_BRACKET_RIGHT  shift 14
+	ARITH_OP  shift 15
 	.  error
 
 
@@ -100,9 +101,7 @@ state 10
 
 state 11
 	expr:  INTEGER.    (9)
-	arith:  INTEGER.ARITH_OP INTEGER 
 
-	ARITH_OP  shift 16
 	.  reduce 9 (src line 103)
 
 
@@ -113,110 +112,118 @@ state 12
 
 
 state 13
-	expr:  arith.    (11)
-
-	.  reduce 11 (src line 119)
-
-
-state 14
 	expr:  IDENTIFIER.    (12)
 	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
 
-	PAREN_LEFT  shift 17
-	.  reduce 12 (src line 123)
+	PAREN_LEFT  shift 16
+	.  reduce 12 (src line 127)
 
 
-state 15
+state 14
 	interpolation:  PROGRAM_BRACKET_LEFT expr PROGRAM_BRACKET_RIGHT.    (7)
 
 	.  reduce 7 (src line 92)
 
 
-state 16
-	arith:  INTEGER ARITH_OP.INTEGER 
-
-	INTEGER  shift 18
-	.  error
-
-
-state 17
-	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
-	args: .    (15)
+state 15
+	expr:  expr ARITH_OP.expr 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 14
+	IDENTIFIER  shift 13
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
-	.  reduce 15 (src line 153)
+	.  error
 
-	arith  goto 13
-	expr  goto 20
+	expr  goto 17
 	interpolation  goto 5
 	literal  goto 4
 	literalModeTop  goto 10
 	literalModeValue  goto 3
-	args  goto 19
+
+state 16
+	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
+	args: .    (14)
+
+	PROGRAM_BRACKET_LEFT  shift 7
+	IDENTIFIER  shift 13
+	INTEGER  shift 11
+	FLOAT  shift 12
+	STRING  shift 6
+	.  reduce 14 (src line 136)
+
+	expr  goto 19
+	interpolation  goto 5
+	literal  goto 4
+	literalModeTop  goto 10
+	literalModeValue  goto 3
+	args  goto 18
+
+17: shift/reduce conflict (shift 15(0), red'n 11(0)) on ARITH_OP
+state 17
+	expr:  expr.ARITH_OP expr 
+	expr:  expr ARITH_OP expr.    (11)
+
+	ARITH_OP  shift 15
+	.  reduce 11 (src line 119)
+
 
 state 18
-	arith:  INTEGER ARITH_OP INTEGER.    (14)
-
-	.  reduce 14 (src line 132)
-
-
-state 19
 	expr:  IDENTIFIER PAREN_LEFT args.PAREN_RIGHT 
 	args:  args.COMMA expr 
 
-	PAREN_RIGHT  shift 21
-	COMMA  shift 22
+	PAREN_RIGHT  shift 20
+	COMMA  shift 21
 	.  error
 
 
-state 20
-	args:  expr.    (17)
+state 19
+	expr:  expr.ARITH_OP expr 
+	args:  expr.    (16)
 
-	.  reduce 17 (src line 161)
+	ARITH_OP  shift 15
+	.  reduce 16 (src line 144)
+
+
+state 20
+	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (13)
+
+	.  reduce 13 (src line 131)
 
 
 state 21
-	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (13)
-
-	.  reduce 13 (src line 127)
-
-
-state 22
 	args:  args COMMA.expr 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 14
+	IDENTIFIER  shift 13
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
 	.  error
 
-	arith  goto 13
-	expr  goto 23
+	expr  goto 22
 	interpolation  goto 5
 	literal  goto 4
 	literalModeTop  goto 10
 	literalModeValue  goto 3
 
-state 23
-	args:  args COMMA expr.    (16)
+state 22
+	expr:  expr.ARITH_OP expr 
+	args:  args COMMA expr.    (15)
 
-	.  reduce 16 (src line 157)
+	ARITH_OP  shift 15
+	.  reduce 15 (src line 140)
 
 
-15 terminals, 9 nonterminals
-19 grammar rules, 24/2000 states
-0 shift/reduce, 0 reduce/reduce conflicts reported
-58 working sets used
-memory: parser 28/30000
-19 extra closures
-27 shift entries, 1 exceptions
+15 terminals, 8 nonterminals
+18 grammar rules, 23/2000 states
+1 shift/reduce, 0 reduce/reduce conflicts reported
+57 working sets used
+memory: parser 30/30000
+18 extra closures
+34 shift entries, 1 exceptions
 13 goto entries
-17 entries saved by goto default
+19 entries saved by goto default
 Optimizer space used: output 26/30000
 26 table entries, 0 zero
-maximum spread: 15, maximum offset: 22
+maximum spread: 15, maximum offset: 21

From 9ddcaf15ebf65e1d64a6645335aeb222b01de416 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 14:33:56 -0800
Subject: [PATCH 3/6] config/lang: fix shift/reduce conflict

---
 config/lang/lang.y   |  2 ++
 config/lang/y.go     | 38 +++++++++++++++++++-------------------
 config/lang/y.output | 40 +++++++++++++++++++---------------------
 3 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/config/lang/lang.y b/config/lang/lang.y
index 96517a76e..9e4b9baaf 100644
--- a/config/lang/lang.y
+++ b/config/lang/lang.y
@@ -27,6 +27,8 @@ import (
 %type <node> expr interpolation literal literalModeTop literalModeValue
 %type <nodeList> args
 
+%left ARITH_OP
+
 %%
 
 top:
diff --git a/config/lang/y.go b/config/lang/y.go
index f9198d8f7..75b450d25 100644
--- a/config/lang/y.go
+++ b/config/lang/y.go
@@ -50,7 +50,7 @@ const parserEofCode = 1
 const parserErrCode = 2
 const parserMaxDepth = 200
 
-//line lang.y:159
+//line lang.y:161
 
 //line yacctab:1
 var parserExca = []int{
@@ -76,7 +76,7 @@ var parserAct = []int{
 var parserPact = []int{
 
 	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 3,
-	-2, -1000, -1000, 10, -1000, -3, -3, -8, -4, -8,
+	-2, -1000, -1000, 10, -1000, -3, -3, -1000, -4, -8,
 	-1000, -3, -8,
 }
 var parserPgo = []int{
@@ -344,7 +344,7 @@ parserdefault:
 	switch parsernt {
 
 	case 1:
-		//line lang.y:33
+		//line lang.y:35
 		{
 			parserResult = &ast.LiteralNode{
 				Value: "",
@@ -353,7 +353,7 @@ parserdefault:
 			}
 		}
 	case 2:
-		//line lang.y:41
+		//line lang.y:43
 		{
 			parserResult = parserS[parserpt-0].node
 
@@ -375,12 +375,12 @@ parserdefault:
 			}
 		}
 	case 3:
-		//line lang.y:64
+		//line lang.y:66
 		{
 			parserVAL.node = parserS[parserpt-0].node
 		}
 	case 4:
-		//line lang.y:68
+		//line lang.y:70
 		{
 			var result []ast.Node
 			if c, ok := parserS[parserpt-1].node.(*ast.Concat); ok {
@@ -395,27 +395,27 @@ parserdefault:
 			}
 		}
 	case 5:
-		//line lang.y:84
+		//line lang.y:86
 		{
 			parserVAL.node = parserS[parserpt-0].node
 		}
 	case 6:
-		//line lang.y:88
+		//line lang.y:90
 		{
 			parserVAL.node = parserS[parserpt-0].node
 		}
 	case 7:
-		//line lang.y:94
+		//line lang.y:96
 		{
 			parserVAL.node = parserS[parserpt-1].node
 		}
 	case 8:
-		//line lang.y:100
+		//line lang.y:102
 		{
 			parserVAL.node = parserS[parserpt-0].node
 		}
 	case 9:
-		//line lang.y:104
+		//line lang.y:106
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(int),
@@ -424,7 +424,7 @@ parserdefault:
 			}
 		}
 	case 10:
-		//line lang.y:112
+		//line lang.y:114
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(float64),
@@ -433,7 +433,7 @@ parserdefault:
 			}
 		}
 	case 11:
-		//line lang.y:120
+		//line lang.y:122
 		{
 			parserVAL.node = &ast.Arithmetic{
 				Op:    parserS[parserpt-1].token.Value.(ast.ArithmeticOp),
@@ -442,32 +442,32 @@ parserdefault:
 			}
 		}
 	case 12:
-		//line lang.y:128
+		//line lang.y:130
 		{
 			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
 		}
 	case 13:
-		//line lang.y:132
+		//line lang.y:134
 		{
 			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
 		}
 	case 14:
-		//line lang.y:137
+		//line lang.y:139
 		{
 			parserVAL.nodeList = nil
 		}
 	case 15:
-		//line lang.y:141
+		//line lang.y:143
 		{
 			parserVAL.nodeList = append(parserS[parserpt-2].nodeList, parserS[parserpt-0].node)
 		}
 	case 16:
-		//line lang.y:145
+		//line lang.y:147
 		{
 			parserVAL.nodeList = append(parserVAL.nodeList, parserS[parserpt-0].node)
 		}
 	case 17:
-		//line lang.y:151
+		//line lang.y:153
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(string),
diff --git a/config/lang/y.output b/config/lang/y.output
index d524d1e2e..64dfe04fc 100644
--- a/config/lang/y.output
+++ b/config/lang/y.output
@@ -5,7 +5,7 @@ state 0
 
 	PROGRAM_BRACKET_LEFT  shift 7
 	STRING  shift 6
-	.  reduce 1 (src line 32)
+	.  reduce 1 (src line 34)
 
 	interpolation  goto 5
 	literal  goto 4
@@ -26,7 +26,7 @@ state 2
 
 	PROGRAM_BRACKET_LEFT  shift 7
 	STRING  shift 6
-	.  reduce 2 (src line 40)
+	.  reduce 2 (src line 42)
 
 	interpolation  goto 5
 	literal  goto 4
@@ -35,25 +35,25 @@ state 2
 state 3
 	literalModeTop:  literalModeValue.    (3)
 
-	.  reduce 3 (src line 62)
+	.  reduce 3 (src line 64)
 
 
 state 4
 	literalModeValue:  literal.    (5)
 
-	.  reduce 5 (src line 82)
+	.  reduce 5 (src line 84)
 
 
 state 5
 	literalModeValue:  interpolation.    (6)
 
-	.  reduce 6 (src line 87)
+	.  reduce 6 (src line 89)
 
 
 state 6
 	literal:  STRING.    (17)
 
-	.  reduce 17 (src line 149)
+	.  reduce 17 (src line 151)
 
 
 state 7
@@ -75,7 +75,7 @@ state 7
 state 8
 	literalModeTop:  literalModeTop literalModeValue.    (4)
 
-	.  reduce 4 (src line 67)
+	.  reduce 4 (src line 69)
 
 
 state 9
@@ -93,7 +93,7 @@ state 10
 
 	PROGRAM_BRACKET_LEFT  shift 7
 	STRING  shift 6
-	.  reduce 8 (src line 98)
+	.  reduce 8 (src line 100)
 
 	interpolation  goto 5
 	literal  goto 4
@@ -102,13 +102,13 @@ state 10
 state 11
 	expr:  INTEGER.    (9)
 
-	.  reduce 9 (src line 103)
+	.  reduce 9 (src line 105)
 
 
 state 12
 	expr:  FLOAT.    (10)
 
-	.  reduce 10 (src line 111)
+	.  reduce 10 (src line 113)
 
 
 state 13
@@ -116,13 +116,13 @@ state 13
 	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
 
 	PAREN_LEFT  shift 16
-	.  reduce 12 (src line 127)
+	.  reduce 12 (src line 129)
 
 
 state 14
 	interpolation:  PROGRAM_BRACKET_LEFT expr PROGRAM_BRACKET_RIGHT.    (7)
 
-	.  reduce 7 (src line 92)
+	.  reduce 7 (src line 94)
 
 
 state 15
@@ -150,7 +150,7 @@ state 16
 	INTEGER  shift 11
 	FLOAT  shift 12
 	STRING  shift 6
-	.  reduce 14 (src line 136)
+	.  reduce 14 (src line 138)
 
 	expr  goto 19
 	interpolation  goto 5
@@ -159,13 +159,11 @@ state 16
 	literalModeValue  goto 3
 	args  goto 18
 
-17: shift/reduce conflict (shift 15(0), red'n 11(0)) on ARITH_OP
 state 17
 	expr:  expr.ARITH_OP expr 
 	expr:  expr ARITH_OP expr.    (11)
 
-	ARITH_OP  shift 15
-	.  reduce 11 (src line 119)
+	.  reduce 11 (src line 121)
 
 
 state 18
@@ -182,13 +180,13 @@ state 19
 	args:  expr.    (16)
 
 	ARITH_OP  shift 15
-	.  reduce 16 (src line 144)
+	.  reduce 16 (src line 146)
 
 
 state 20
 	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (13)
 
-	.  reduce 13 (src line 131)
+	.  reduce 13 (src line 133)
 
 
 state 21
@@ -212,16 +210,16 @@ state 22
 	args:  args COMMA expr.    (15)
 
 	ARITH_OP  shift 15
-	.  reduce 15 (src line 140)
+	.  reduce 15 (src line 142)
 
 
 15 terminals, 8 nonterminals
 18 grammar rules, 23/2000 states
-1 shift/reduce, 0 reduce/reduce conflicts reported
+0 shift/reduce, 0 reduce/reduce conflicts reported
 57 working sets used
 memory: parser 30/30000
 18 extra closures
-34 shift entries, 1 exceptions
+33 shift entries, 1 exceptions
 13 goto entries
 19 entries saved by goto default
 Optimizer space used: output 26/30000

From 6750318bb50bb6e21eb9d3247acd0d71acdca3a4 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 14:34:45 -0800
Subject: [PATCH 4/6] config/lang: add test with expressions

---
 config/lang/eval_test.go | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/config/lang/eval_test.go b/config/lang/eval_test.go
index 3446be9d2..6af2c714b 100644
--- a/config/lang/eval_test.go
+++ b/config/lang/eval_test.go
@@ -95,6 +95,21 @@ func TestEval(t *testing.T) {
 			ast.TypeString,
 		},
 
+		{
+			"foo ${bar+1}",
+			&ast.BasicScope{
+				VarMap: map[string]ast.Variable{
+					"bar": ast.Variable{
+						Value: 41,
+						Type:  ast.TypeInt,
+					},
+				},
+			},
+			false,
+			"foo 42",
+			ast.TypeString,
+		},
+
 		{
 			"foo ${rand()}",
 			&ast.BasicScope{

From 3c4a036fb507fabe3c12f73869c316bbba3362d5 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 14:39:04 -0800
Subject: [PATCH 5/6] config/lang: add (expr) for order of ops

---
 config/lang/eval_test.go |  16 +++
 config/lang/lang.y       |   6 +-
 config/lang/y.go         |  73 ++++++------
 config/lang/y.output     | 242 ++++++++++++++++++++++-----------------
 4 files changed, 199 insertions(+), 138 deletions(-)

diff --git a/config/lang/eval_test.go b/config/lang/eval_test.go
index 6af2c714b..8a3195fe1 100644
--- a/config/lang/eval_test.go
+++ b/config/lang/eval_test.go
@@ -95,6 +95,22 @@ func TestEval(t *testing.T) {
 			ast.TypeString,
 		},
 
+		{
+			"foo ${42+2*2}",
+			nil,
+			false,
+			"foo 88",
+			ast.TypeString,
+		},
+
+		{
+			"foo ${42+(2*2)}",
+			nil,
+			false,
+			"foo 46",
+			ast.TypeString,
+		},
+
 		{
 			"foo ${bar+1}",
 			&ast.BasicScope{
diff --git a/config/lang/lang.y b/config/lang/lang.y
index 9e4b9baaf..c531860e5 100644
--- a/config/lang/lang.y
+++ b/config/lang/lang.y
@@ -98,7 +98,11 @@ interpolation:
     }
 
 expr:
-    literalModeTop
+    PAREN_LEFT expr PAREN_RIGHT
+    {
+        $$ = $2
+    }
+|   literalModeTop
     {
         $$ = $1
     }
diff --git a/config/lang/y.go b/config/lang/y.go
index 75b450d25..e7dd185ae 100644
--- a/config/lang/y.go
+++ b/config/lang/y.go
@@ -50,7 +50,7 @@ const parserEofCode = 1
 const parserErrCode = 2
 const parserMaxDepth = 200
 
-//line lang.y:161
+//line lang.y:165
 
 //line yacctab:1
 var parserExca = []int{
@@ -59,51 +59,51 @@ var parserExca = []int{
 	-2, 0,
 }
 
-const parserNprod = 18
+const parserNprod = 19
 const parserPrivate = 57344
 
 var parserTokenNames []string
 var parserStates []string
 
-const parserLast = 26
+const parserLast = 30
 
 var parserAct = []int{
 
-	9, 7, 7, 15, 3, 20, 21, 8, 14, 13,
-	11, 12, 6, 6, 15, 8, 17, 19, 16, 10,
-	2, 1, 22, 18, 4, 5,
+	9, 20, 16, 16, 7, 7, 3, 18, 10, 8,
+	1, 17, 14, 12, 13, 6, 6, 19, 8, 22,
+	15, 23, 24, 11, 2, 25, 16, 21, 4, 5,
 }
 var parserPact = []int{
 
-	-2, -1000, -2, -1000, -1000, -1000, -1000, -3, -1000, 3,
-	-2, -1000, -1000, 10, -1000, -3, -3, -1000, -4, -8,
-	-1000, -3, -8,
+	1, -1000, 1, -1000, -1000, -1000, -1000, 0, -1000, 15,
+	0, 1, -1000, -1000, -1, -1000, 0, -8, 0, -1000,
+	-1000, 12, -9, -1000, 0, -9,
 }
 var parserPgo = []int{
 
-	0, 0, 25, 24, 19, 4, 23, 21,
+	0, 0, 29, 28, 23, 6, 27, 10,
 }
 var parserR1 = []int{
 
 	0, 7, 7, 4, 4, 5, 5, 2, 1, 1,
-	1, 1, 1, 1, 6, 6, 6, 3,
+	1, 1, 1, 1, 1, 6, 6, 6, 3,
 }
 var parserR2 = []int{
 
-	0, 0, 1, 1, 2, 1, 1, 3, 1, 1,
-	1, 3, 1, 4, 0, 3, 1, 1,
+	0, 0, 1, 1, 2, 1, 1, 3, 3, 1,
+	1, 1, 3, 1, 4, 0, 3, 1, 1,
 }
 var parserChk = []int{
 
 	-1000, -7, -4, -5, -3, -2, 15, 4, -5, -1,
-	-4, 13, 14, 12, 5, 11, 8, -1, -6, -1,
-	9, 10, -1,
+	8, -4, 13, 14, 12, 5, 11, -1, 8, -1,
+	9, -6, -1, 9, 10, -1,
 }
 var parserDef = []int{
 
-	1, -2, 2, 3, 5, 6, 17, 0, 4, 0,
-	8, 9, 10, 12, 7, 0, 14, 11, 0, 16,
-	13, 0, 15,
+	1, -2, 2, 3, 5, 6, 18, 0, 4, 0,
+	0, 9, 10, 11, 13, 7, 0, 0, 15, 12,
+	8, 0, 17, 14, 0, 16,
 }
 var parserTok1 = []int{
 
@@ -412,10 +412,15 @@ parserdefault:
 	case 8:
 		//line lang.y:102
 		{
-			parserVAL.node = parserS[parserpt-0].node
+			parserVAL.node = parserS[parserpt-1].node
 		}
 	case 9:
 		//line lang.y:106
+		{
+			parserVAL.node = parserS[parserpt-0].node
+		}
+	case 10:
+		//line lang.y:110
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(int),
@@ -423,8 +428,8 @@ parserdefault:
 				Posx:  parserS[parserpt-0].token.Pos,
 			}
 		}
-	case 10:
-		//line lang.y:114
+	case 11:
+		//line lang.y:118
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(float64),
@@ -432,8 +437,8 @@ parserdefault:
 				Posx:  parserS[parserpt-0].token.Pos,
 			}
 		}
-	case 11:
-		//line lang.y:122
+	case 12:
+		//line lang.y:126
 		{
 			parserVAL.node = &ast.Arithmetic{
 				Op:    parserS[parserpt-1].token.Value.(ast.ArithmeticOp),
@@ -441,33 +446,33 @@ parserdefault:
 				Posx:  parserS[parserpt-2].node.Pos(),
 			}
 		}
-	case 12:
-		//line lang.y:130
-		{
-			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
-		}
 	case 13:
 		//line lang.y:134
 		{
-			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
+			parserVAL.node = &ast.VariableAccess{Name: parserS[parserpt-0].token.Value.(string), Posx: parserS[parserpt-0].token.Pos}
 		}
 	case 14:
-		//line lang.y:139
+		//line lang.y:138
 		{
-			parserVAL.nodeList = nil
+			parserVAL.node = &ast.Call{Func: parserS[parserpt-3].token.Value.(string), Args: parserS[parserpt-1].nodeList, Posx: parserS[parserpt-3].token.Pos}
 		}
 	case 15:
 		//line lang.y:143
 		{
-			parserVAL.nodeList = append(parserS[parserpt-2].nodeList, parserS[parserpt-0].node)
+			parserVAL.nodeList = nil
 		}
 	case 16:
 		//line lang.y:147
 		{
-			parserVAL.nodeList = append(parserVAL.nodeList, parserS[parserpt-0].node)
+			parserVAL.nodeList = append(parserS[parserpt-2].nodeList, parserS[parserpt-0].node)
 		}
 	case 17:
-		//line lang.y:153
+		//line lang.y:151
+		{
+			parserVAL.nodeList = append(parserVAL.nodeList, parserS[parserpt-0].node)
+		}
+	case 18:
+		//line lang.y:157
 		{
 			parserVAL.node = &ast.LiteralNode{
 				Value: parserS[parserpt-0].token.Value.(string),
diff --git a/config/lang/y.output b/config/lang/y.output
index 64dfe04fc..17352390d 100644
--- a/config/lang/y.output
+++ b/config/lang/y.output
@@ -51,25 +51,26 @@ state 5
 
 
 state 6
-	literal:  STRING.    (17)
+	literal:  STRING.    (18)
 
-	.  reduce 17 (src line 151)
+	.  reduce 18 (src line 155)
 
 
 state 7
 	interpolation:  PROGRAM_BRACKET_LEFT.expr PROGRAM_BRACKET_RIGHT 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
-	INTEGER  shift 11
-	FLOAT  shift 12
+	PAREN_LEFT  shift 10
+	IDENTIFIER  shift 14
+	INTEGER  shift 12
+	FLOAT  shift 13
 	STRING  shift 6
 	.  error
 
 	expr  goto 9
 	interpolation  goto 5
 	literal  goto 4
-	literalModeTop  goto 10
+	literalModeTop  goto 11
 	literalModeValue  goto 3
 
 state 8
@@ -82,146 +83,181 @@ state 9
 	interpolation:  PROGRAM_BRACKET_LEFT expr.PROGRAM_BRACKET_RIGHT 
 	expr:  expr.ARITH_OP expr 
 
-	PROGRAM_BRACKET_RIGHT  shift 14
-	ARITH_OP  shift 15
+	PROGRAM_BRACKET_RIGHT  shift 15
+	ARITH_OP  shift 16
 	.  error
 
 
 state 10
-	literalModeTop:  literalModeTop.literalModeValue 
-	expr:  literalModeTop.    (8)
+	expr:  PAREN_LEFT.expr PAREN_RIGHT 
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	STRING  shift 6
-	.  reduce 8 (src line 100)
-
-	interpolation  goto 5
-	literal  goto 4
-	literalModeValue  goto 8
-
-state 11
-	expr:  INTEGER.    (9)
-
-	.  reduce 9 (src line 105)
-
-
-state 12
-	expr:  FLOAT.    (10)
-
-	.  reduce 10 (src line 113)
-
-
-state 13
-	expr:  IDENTIFIER.    (12)
-	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
-
-	PAREN_LEFT  shift 16
-	.  reduce 12 (src line 129)
-
-
-state 14
-	interpolation:  PROGRAM_BRACKET_LEFT expr PROGRAM_BRACKET_RIGHT.    (7)
-
-	.  reduce 7 (src line 94)
-
-
-state 15
-	expr:  expr ARITH_OP.expr 
-
-	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
-	INTEGER  shift 11
-	FLOAT  shift 12
+	PAREN_LEFT  shift 10
+	IDENTIFIER  shift 14
+	INTEGER  shift 12
+	FLOAT  shift 13
 	STRING  shift 6
 	.  error
 
 	expr  goto 17
 	interpolation  goto 5
 	literal  goto 4
-	literalModeTop  goto 10
+	literalModeTop  goto 11
 	literalModeValue  goto 3
 
-state 16
-	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
-	args: .    (14)
+state 11
+	literalModeTop:  literalModeTop.literalModeValue 
+	expr:  literalModeTop.    (9)
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
-	INTEGER  shift 11
-	FLOAT  shift 12
 	STRING  shift 6
-	.  reduce 14 (src line 138)
+	.  reduce 9 (src line 105)
+
+	interpolation  goto 5
+	literal  goto 4
+	literalModeValue  goto 8
+
+state 12
+	expr:  INTEGER.    (10)
+
+	.  reduce 10 (src line 109)
+
+
+state 13
+	expr:  FLOAT.    (11)
+
+	.  reduce 11 (src line 117)
+
+
+state 14
+	expr:  IDENTIFIER.    (13)
+	expr:  IDENTIFIER.PAREN_LEFT args PAREN_RIGHT 
+
+	PAREN_LEFT  shift 18
+	.  reduce 13 (src line 133)
+
+
+state 15
+	interpolation:  PROGRAM_BRACKET_LEFT expr PROGRAM_BRACKET_RIGHT.    (7)
+
+	.  reduce 7 (src line 94)
+
+
+state 16
+	expr:  expr ARITH_OP.expr 
+
+	PROGRAM_BRACKET_LEFT  shift 7
+	PAREN_LEFT  shift 10
+	IDENTIFIER  shift 14
+	INTEGER  shift 12
+	FLOAT  shift 13
+	STRING  shift 6
+	.  error
 
 	expr  goto 19
 	interpolation  goto 5
 	literal  goto 4
-	literalModeTop  goto 10
+	literalModeTop  goto 11
 	literalModeValue  goto 3
-	args  goto 18
 
 state 17
+	expr:  PAREN_LEFT expr.PAREN_RIGHT 
 	expr:  expr.ARITH_OP expr 
-	expr:  expr ARITH_OP expr.    (11)
 
-	.  reduce 11 (src line 121)
+	PAREN_RIGHT  shift 20
+	ARITH_OP  shift 16
+	.  error
 
 
 state 18
-	expr:  IDENTIFIER PAREN_LEFT args.PAREN_RIGHT 
-	args:  args.COMMA expr 
-
-	PAREN_RIGHT  shift 20
-	COMMA  shift 21
-	.  error
-
-
-state 19
-	expr:  expr.ARITH_OP expr 
-	args:  expr.    (16)
-
-	ARITH_OP  shift 15
-	.  reduce 16 (src line 146)
-
-
-state 20
-	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (13)
-
-	.  reduce 13 (src line 133)
-
-
-state 21
-	args:  args COMMA.expr 
+	expr:  IDENTIFIER PAREN_LEFT.args PAREN_RIGHT 
+	args: .    (15)
 
 	PROGRAM_BRACKET_LEFT  shift 7
-	IDENTIFIER  shift 13
-	INTEGER  shift 11
-	FLOAT  shift 12
+	PAREN_LEFT  shift 10
+	IDENTIFIER  shift 14
+	INTEGER  shift 12
+	FLOAT  shift 13
 	STRING  shift 6
-	.  error
+	.  reduce 15 (src line 142)
 
 	expr  goto 22
 	interpolation  goto 5
 	literal  goto 4
-	literalModeTop  goto 10
+	literalModeTop  goto 11
 	literalModeValue  goto 3
+	args  goto 21
+
+state 19
+	expr:  expr.ARITH_OP expr 
+	expr:  expr ARITH_OP expr.    (12)
+
+	.  reduce 12 (src line 125)
+
+
+state 20
+	expr:  PAREN_LEFT expr PAREN_RIGHT.    (8)
+
+	.  reduce 8 (src line 100)
+
+
+state 21
+	expr:  IDENTIFIER PAREN_LEFT args.PAREN_RIGHT 
+	args:  args.COMMA expr 
+
+	PAREN_RIGHT  shift 23
+	COMMA  shift 24
+	.  error
+
 
 state 22
 	expr:  expr.ARITH_OP expr 
-	args:  args COMMA expr.    (15)
+	args:  expr.    (17)
 
-	ARITH_OP  shift 15
-	.  reduce 15 (src line 142)
+	ARITH_OP  shift 16
+	.  reduce 17 (src line 150)
+
+
+state 23
+	expr:  IDENTIFIER PAREN_LEFT args PAREN_RIGHT.    (14)
+
+	.  reduce 14 (src line 137)
+
+
+state 24
+	args:  args COMMA.expr 
+
+	PROGRAM_BRACKET_LEFT  shift 7
+	PAREN_LEFT  shift 10
+	IDENTIFIER  shift 14
+	INTEGER  shift 12
+	FLOAT  shift 13
+	STRING  shift 6
+	.  error
+
+	expr  goto 25
+	interpolation  goto 5
+	literal  goto 4
+	literalModeTop  goto 11
+	literalModeValue  goto 3
+
+state 25
+	expr:  expr.ARITH_OP expr 
+	args:  args COMMA expr.    (16)
+
+	ARITH_OP  shift 16
+	.  reduce 16 (src line 146)
 
 
 15 terminals, 8 nonterminals
-18 grammar rules, 23/2000 states
+19 grammar rules, 26/2000 states
 0 shift/reduce, 0 reduce/reduce conflicts reported
 57 working sets used
-memory: parser 30/30000
-18 extra closures
-33 shift entries, 1 exceptions
-13 goto entries
-19 entries saved by goto default
-Optimizer space used: output 26/30000
-26 table entries, 0 zero
-maximum spread: 15, maximum offset: 21
+memory: parser 35/30000
+21 extra closures
+45 shift entries, 1 exceptions
+14 goto entries
+23 entries saved by goto default
+Optimizer space used: output 30/30000
+30 table entries, 0 zero
+maximum spread: 15, maximum offset: 24

From 5848cba6ad55be9853da844854f6c0291210ac38 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 26 Feb 2015 15:17:37 -0800
Subject: [PATCH 6/6] config/lang: add modulo

---
 config/lang/ast/arithmetic_op.go | 1 +
 config/lang/builtins.go          | 2 ++
 config/lang/check_types.go       | 5 +++++
 config/lang/eval_test.go         | 8 ++++++++
 config/lang/lex.go               | 3 +++
 5 files changed, 19 insertions(+)

diff --git a/config/lang/ast/arithmetic_op.go b/config/lang/ast/arithmetic_op.go
index 920b1d56e..e36dd42dc 100644
--- a/config/lang/ast/arithmetic_op.go
+++ b/config/lang/ast/arithmetic_op.go
@@ -9,4 +9,5 @@ const (
 	ArithmeticOpSub
 	ArithmeticOpMul
 	ArithmeticOpDiv
+	ArithmeticOpMod
 )
diff --git a/config/lang/builtins.go b/config/lang/builtins.go
index e14aba0d8..bf918c9c7 100644
--- a/config/lang/builtins.go
+++ b/config/lang/builtins.go
@@ -77,6 +77,8 @@ func builtinIntMath() ast.Function {
 					result *= arg
 				case ast.ArithmeticOpDiv:
 					result /= arg
+				case ast.ArithmeticOpMod:
+					result = result % arg
 				}
 			}
 
diff --git a/config/lang/check_types.go b/config/lang/check_types.go
index 3b6eefbf0..f5cf16680 100644
--- a/config/lang/check_types.go
+++ b/config/lang/check_types.go
@@ -131,6 +131,11 @@ func (tc *typeCheckArithmetic) TypeCheck(v *TypeCheck) (ast.Node, error) {
 		}
 	}
 
+	// Modulo doesn't work for floats
+	if mathType == ast.TypeFloat && tc.n.Op == ast.ArithmeticOpMod {
+		return nil, fmt.Errorf("modulo cannot be used with floats")
+	}
+
 	// Return type
 	v.StackPush(mathType)
 
diff --git a/config/lang/eval_test.go b/config/lang/eval_test.go
index 8a3195fe1..602880cf2 100644
--- a/config/lang/eval_test.go
+++ b/config/lang/eval_test.go
@@ -71,6 +71,14 @@ func TestEval(t *testing.T) {
 			ast.TypeString,
 		},
 
+		{
+			"foo ${42%4}",
+			nil,
+			false,
+			"foo 2",
+			ast.TypeString,
+		},
+
 		{
 			"foo ${42.0+1.0}",
 			nil,
diff --git a/config/lang/lex.go b/config/lang/lex.go
index 6b30f2a4c..6e70acfbc 100644
--- a/config/lang/lex.go
+++ b/config/lang/lex.go
@@ -180,6 +180,9 @@ func (x *parserLex) lexModeInterpolation(yylval *parserSymType) int {
 		case '/':
 			yylval.token = &parserToken{Value: ast.ArithmeticOpDiv}
 			return ARITH_OP
+		case '%':
+			yylval.token = &parserToken{Value: ast.ArithmeticOpMod}
+			return ARITH_OP
 		default:
 			x.backup()
 			return x.lexId(yylval)