# `Expression.Sigil`

Provides the `~EXPR` sigil for compile-time expression validation
and optional pre-parsing.

## Usage

    import Expression.Sigil

    # Validate syntax at compile time, return string at runtime
    expr = ~EXPR"SUM(contact.age, 10)"

    # Pre-parse to AST at compile time — zero runtime parse cost
    ast = ~EXPR"SUM(contact.age, 10)"c

    # Compile error on invalid syntax
    bad = ~EXPR"SUM(contact.age,"
    #=> ** (CompileError) invalid expression: ...

The default mode validates that the expression is syntactically correct
during compilation but returns the original string for runtime parsing.
This catches typos and syntax errors at build time.

The `c` modifier pre-compiles the expression to its AST representation,
eliminating runtime parsing entirely. Use this for expressions embedded
in Elixir source that are evaluated repeatedly.

# `sigil_EXPR`
*macro* 

Sigil for compile-time expression validation.

Without modifiers, validates syntax and returns the string.
With the `c` modifier, returns the pre-parsed AST.

---

*Consult [api-reference.md](api-reference.md) for complete listing*