158 lines
3.9 KiB
Markdown
158 lines
3.9 KiB
Markdown
---
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layout: "language"
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page_title: "Expressions Landing Page - Configuration Language"
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sidebar_current: "docs-config-expressions"
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---
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# Expressions Landing Page
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To improve navigation, we've split the old Expressions page into several smaller
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pages.
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<a id="types-and-values"></a>
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<a id="advanced-type-details"></a>
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<a id="type-conversion"></a>
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<a id="literal-expressions"></a>
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<a id="indices-and-attributes"></a>
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## Types and Values, Literal Expressions, Indices and Attributes
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Terraform's types are `string`, `number`, `bool`, `list`, `tuple`, `map`,
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`object`, and `null`.
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This information has moved to
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[Types and Values](/docs/configuration/expressions/types.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="references-to-named-values"></a>
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<a id="local-named-values"></a>
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<a id="named-values-and-dependencies"></a>
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<a id="references-to-resource-attributes"></a>
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<a id="local-named-values-1"></a>
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<a id="values-not-yet-known"></a>
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## References to Named Values (Resource Attributes, Variables, etc.)
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You can refer to certain values by name, like `var.some_variable` or
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`aws_instance.example.ami`.
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This information has moved to
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[References to Values](/docs/configuration/expressions/references.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="arithmetic-operators"></a>
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<a id="equality-operators"></a>
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<a id="comparison-operators"></a>
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<a id="logical-operators"></a>
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## Arithmetic and Logical Operators
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Operators are expressions that transform other expressions, like adding two
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numbers (`+`) or comparing two values to get a bool (`==`, `>=`, etc.).
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This information has moved to
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[Operators](/docs/configuration/expressions/references.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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## Conditional Expressions
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The `condition ? true_val : false_val` expression chooses between two
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expressions based on a bool condition.
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This information has moved to
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[Conditional Expressions](/docs/configuration/expressions/conditionals.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="expanding-function-arguments"></a>
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<a id="available-functions"></a>
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## Function Calls
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Terraform's functions can be called like `function_name(arg1, arg2)`.
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This information has moved to
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[Function Calls](/docs/configuration/expressions/function-calls.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="for-expressions"></a>
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## `for` Expressions
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Expressions like `[for s in var.list : upper(s)]` can transform a complex type
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value into another complex type value.
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This information has moved to
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[For Expressions](/docs/configuration/expressions/for.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="splat-expressions"></a>
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<a id="legacy-attribute-only-splat-expressions"></a>
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## Splat Expressions
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Expressions like `var.list[*].id` can extract simpler collections from complex
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collections.
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This information has moved to
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[Splat Expressions](/docs/configuration/expressions/splat.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="dynamic-blocks"></a>
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<a id="best-practices-for-dynamic-blocks"></a>
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## `dynamic` Blocks
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The special `dynamic` block type serves the same purpose as a `for` expression,
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except it creates multiple repeatable nested blocks instead of a complex value.
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This information has moved to
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[Dynamic Blocks](/docs/configuration/expressions/dynamic-blocks.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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<a id="string-literals"></a>
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<a id="string-templates"></a>
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<a id="interpolation"></a>
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<a id="directives"></a>
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## String Literals and String Templates
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Strings can be `"double-quoted"` or
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```hcl
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<<EOT
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heredocs
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EOT
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```
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Strings can also include escape sequences like `\n`, interpolation sequences
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(`${ ... }`), and template sequences (`%{ ... }`).
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This information has moved to
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[Strings and Templates](/docs/configuration/expressions/strings.html).
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<div style="height: 100vh; margin: 0; padding: 0;"></div>
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