config/lang: make TypeCheck implementable by other nodes
This commit is contained in:
Mitchell Hashimoto
parent
57adfe53f6
commit
4302dbaf2a
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@ -24,9 +24,19 @@ type TypeCheck struct {
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// value is the function to call (which must be registered in the Scope).
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Implicit map[ast.Type]map[ast.Type]string
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stack []ast.Type
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err error
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lock sync.Mutex
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// Stack of types. This shouldn't be used directly except by implementations
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// of TypeCheckNode.
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Stack []ast.Type
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err error
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lock sync.Mutex
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}
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// TypeCheckNode is the interface that must be implemented by any
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// ast.Node that wants to support type-checking. If the type checker
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// encounters a node that doesn't implement this, it will error.
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type TypeCheckNode interface {
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TypeCheck(*TypeCheck) (ast.Node, error)
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}
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func (v *TypeCheck) Visit(root ast.Node) error {
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@ -42,49 +52,69 @@ func (v *TypeCheck) visit(raw ast.Node) ast.Node {
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return raw
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}
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var result ast.Node
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var err error
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switch n := raw.(type) {
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case *ast.Call:
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v.visitCall(n)
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tc := &typeCheckCall{n}
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result, err = tc.TypeCheck(v)
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case *ast.Concat:
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v.visitConcat(n)
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tc := &typeCheckConcat{n}
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result, err = tc.TypeCheck(v)
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case *ast.LiteralNode:
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v.visitLiteral(n)
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tc := &typeCheckLiteral{n}
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result, err = tc.TypeCheck(v)
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case *ast.VariableAccess:
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v.visitVariableAccess(n)
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tc := &typeCheckVariableAccess{n}
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result, err = tc.TypeCheck(v)
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default:
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v.createErr(n, fmt.Sprintf("unknown node: %#v", raw))
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tc, ok := raw.(TypeCheckNode)
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if !ok {
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err = fmt.Errorf("unknown node: %#v", raw)
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break
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}
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result, err = tc.TypeCheck(v)
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}
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return raw
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if err != nil {
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pos := raw.Pos()
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v.err = fmt.Errorf("At column %d, line %d: %s",
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pos.Column, pos.Line, err)
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}
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return result
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}
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func (v *TypeCheck) visitCall(n *ast.Call) {
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type typeCheckCall struct {
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n *ast.Call
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}
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func (tc *typeCheckCall) TypeCheck(v *TypeCheck) (ast.Node, error) {
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// Look up the function in the map
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function, ok := v.Scope.LookupFunc(n.Func)
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function, ok := v.Scope.LookupFunc(tc.n.Func)
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if !ok {
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v.createErr(n, fmt.Sprintf("unknown function called: %s", n.Func))
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return
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return nil, fmt.Errorf("unknown function called: %s", tc.n.Func)
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}
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// The arguments are on the stack in reverse order, so pop them off.
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args := make([]ast.Type, len(n.Args))
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for i, _ := range n.Args {
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args[len(n.Args)-1-i] = v.stackPop()
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args := make([]ast.Type, len(tc.n.Args))
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for i, _ := range tc.n.Args {
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args[len(tc.n.Args)-1-i] = v.StackPop()
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}
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// Verify the args
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for i, expected := range function.ArgTypes {
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if args[i] != expected {
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cn := v.implicitConversion(args[i], expected, n.Args[i])
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cn := v.ImplicitConversion(args[i], expected, tc.n.Args[i])
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if cn != nil {
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n.Args[i] = cn
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tc.n.Args[i] = cn
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continue
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}
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v.createErr(n, fmt.Sprintf(
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return nil, fmt.Errorf(
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"%s: argument %d should be %s, got %s",
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n.Func, i+1, expected, args[i]))
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return
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tc.n.Func, i+1, expected, args[i])
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}
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}
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@ -94,75 +124,86 @@ func (v *TypeCheck) visitCall(n *ast.Call) {
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for i, t := range args {
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if t != function.VariadicType {
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realI := i + len(function.ArgTypes)
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cn := v.implicitConversion(
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t, function.VariadicType, n.Args[realI])
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cn := v.ImplicitConversion(
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t, function.VariadicType, tc.n.Args[realI])
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if cn != nil {
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n.Args[realI] = cn
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tc.n.Args[realI] = cn
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continue
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}
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v.createErr(n, fmt.Sprintf(
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return nil, fmt.Errorf(
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"%s: argument %d should be %s, got %s",
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n.Func, realI,
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function.VariadicType, t))
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return
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tc.n.Func, realI,
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function.VariadicType, t)
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}
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}
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}
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// Return type
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v.stackPush(function.ReturnType)
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v.StackPush(function.ReturnType)
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return tc.n, nil
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}
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func (v *TypeCheck) visitConcat(n *ast.Concat) {
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type typeCheckConcat struct {
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n *ast.Concat
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}
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func (tc *typeCheckConcat) TypeCheck(v *TypeCheck) (ast.Node, error) {
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n := tc.n
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types := make([]ast.Type, len(n.Exprs))
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for i, _ := range n.Exprs {
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types[len(n.Exprs)-1-i] = v.stackPop()
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types[len(n.Exprs)-1-i] = v.StackPop()
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}
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// All concat args must be strings, so validate that
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for i, t := range types {
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if t != ast.TypeString {
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cn := v.implicitConversion(t, ast.TypeString, n.Exprs[i])
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cn := v.ImplicitConversion(t, ast.TypeString, n.Exprs[i])
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if cn != nil {
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n.Exprs[i] = cn
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continue
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}
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v.createErr(n, fmt.Sprintf(
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"argument %d must be a string", i+1))
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return
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return nil, fmt.Errorf(
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"argument %d must be a string", i+1)
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}
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}
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// This always results in type string
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v.stackPush(ast.TypeString)
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v.StackPush(ast.TypeString)
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return n, nil
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}
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func (v *TypeCheck) visitLiteral(n *ast.LiteralNode) {
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v.stackPush(n.Typex)
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type typeCheckLiteral struct {
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n *ast.LiteralNode
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}
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func (v *TypeCheck) visitVariableAccess(n *ast.VariableAccess) {
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func (tc *typeCheckLiteral) TypeCheck(v *TypeCheck) (ast.Node, error) {
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v.StackPush(tc.n.Typex)
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return tc.n, nil
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}
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type typeCheckVariableAccess struct {
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n *ast.VariableAccess
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}
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func (tc *typeCheckVariableAccess) TypeCheck(v *TypeCheck) (ast.Node, error) {
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// Look up the variable in the map
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variable, ok := v.Scope.LookupVar(n.Name)
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variable, ok := v.Scope.LookupVar(tc.n.Name)
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if !ok {
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v.createErr(n, fmt.Sprintf(
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"unknown variable accessed: %s", n.Name))
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return
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return nil, fmt.Errorf(
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"unknown variable accessed: %s", tc.n.Name)
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}
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// Add the type to the stack
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v.stackPush(variable.Type)
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v.StackPush(variable.Type)
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return tc.n, nil
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}
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func (v *TypeCheck) createErr(n ast.Node, str string) {
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pos := n.Pos()
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v.err = fmt.Errorf("At column %d, line %d: %s",
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pos.Column, pos.Line, str)
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}
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func (v *TypeCheck) implicitConversion(
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func (v *TypeCheck) ImplicitConversion(
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actual ast.Type, expected ast.Type, n ast.Node) ast.Node {
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if v.Implicit == nil {
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return nil
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@ -186,16 +227,16 @@ func (v *TypeCheck) implicitConversion(
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}
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func (v *TypeCheck) reset() {
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v.stack = nil
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v.Stack = nil
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v.err = nil
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}
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func (v *TypeCheck) stackPush(t ast.Type) {
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v.stack = append(v.stack, t)
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func (v *TypeCheck) StackPush(t ast.Type) {
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v.Stack = append(v.Stack, t)
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}
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func (v *TypeCheck) stackPop() ast.Type {
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func (v *TypeCheck) StackPop() ast.Type {
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var x ast.Type
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x, v.stack = v.stack[len(v.stack)-1], v.stack[:len(v.stack)-1]
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x, v.Stack = v.Stack[len(v.Stack)-1], v.Stack[:len(v.Stack)-1]
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return x
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}
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