Functions

A function is the top-level unit of compilation. It has a name, typed parameters, an optional return type, and a body organized as a hierarchical CFG.

func @name(param_types...) -> ret_type {
  ...
}

• Name: prefixed with @ in text format.
• Parameters: a list of types. Parameter values are created via param instructions. Parameters may optionally carry source-level names for readability (see below).
• Return type: optional. Functions with no return type return void.
• Body: blocks and nested regions directly inside the function braces. The implicit top-level function region is not written in the text format.

Named Parameters

When source-level parameter names are available (e.g., extracted from MIR debug info), they are displayed in the function signature and param instructions:

func @add(%a: int, %b: int) -> int {
  bb0:
    v0 = param %a
    v1 = param %b
    v2 = add v0, v1
    ret v2
}

Parameter names are prefixed with % in text format. When no name is available, the numeric ABI index is used as a fallback:

func @add(int, int) -> int {
  bb0:
    v0 = param 0
    v1 = param 1

Named parameters are display-only — the internal representation uses numeric ABI indices (Op::Param(u32)) for code generation.