Module exec 

Exec runtime: render the parsed Exec mini-language into shell text and run it through /bin/sh.

The pipeline AST itself is produced by crate::parse::exec; this module is concerned with turning typed request values into shell-safe words.

Semantics:

• A ValueRef is resolved against an ExecContext (query/path/header/ var maps and a BodyValue).
• A Text token is always emitted as one argv element. Missing interpolations render as the empty string.
• A [..] Group token is used for shell words that contain interpolation. It is emitted only if every interpolation resolves; otherwise the whole group is omitted.
• Request values interpolated into shell text are single-quoted. Literal shell syntax written by the spec author remains literal shell syntax.
• A binary body used outside stdin is written to a temp file and the path is interpolated as a quoted shell word.
• Pipeline stages are wired stdin → stdout. A bare Source stage ($ | cmd) feeds a value as stdin to the next command.

Structs

ExecContext

ExecOutput

Enums

BodyValue

Functions

build_argv

preview_pipeline

Render a human-readable, non-executing preview of pipeline against ctx. Used by --dry-run to log the commands that would have run.

run_pipeline