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Control Flow

Control flow in Mutant is centered on if and else expressions that map to branching behavior in the compiler and VM. The current language model keeps control flow intentionally small and explicit. That makes it easier to reason about how a source branch becomes bytecode and how the runtime chooses a path when a condition evaluates. Pointers if and else are the core branching constructs in the current spec. Branches are evaluated by the compiler and VM together, not by a separate macro or preprocessing stage.

Source repo
aoiflux/mutant
Source path
docs/BYTECODE_IR.md
Last reviewed
2026-07-03
Freshness tier
high

Control flow in Mutant is centered on if and else expressions that map to branching behavior in the compiler and VM.

The current language model keeps control flow intentionally small and explicit. That makes it easier to reason about how a source branch becomes bytecode and how the runtime chooses a path when a condition evaluates.

Pointers

  • if and else are the core branching constructs in the current spec.
  • Branches are evaluated by the compiler and VM together, not by a separate macro or preprocessing stage.
  • The upstream bytecode reference is the source of truth for any branch opcode or operand change.

Example

if (1 == 1) {
  putf("yes");
} else {
  putf("no");
}

Flow

flowchart TD A[Source if/else] --> B[Compiler emits branch bytecode] B --> C[VM evaluates condition] C -->|true| D[Run then branch] C -->|false| E[Run else branch]

Canonical Source