`selectGuardedArm()`

Function in Variants

Recover the arm a set of defined macros selects from an emitGuarded source.

import { selectGuardedArm } from 'typeshade'

The signature, the description and the examples come from the compiler's own source at commit 26de7be8.

Syntax

function selectGuardedArm(source: string, defined: Iterable<string>): string | undefined

Parameters

source string: output of VariantFamily.emitGuarded.
defined Iterable<string>: the macro names the host would have defined.

Return value

string | undefined

the selected arm’s text, or undefined when no arm matches.

Exceptions

Error: Error when a condition in source is not of the form the ladder generates.

Description

Understands only the ladder shape emitGuarded generates: #if, #elif and #endif at column 0, with conditions built from defined(X) and !defined(X) joined by &&. Use it to assert, in a test or a build step, that the arm the host’s defines select equals the standalone variant from VariantFamily.emit, without running a compiler.

Source

src/core/variant-family.ts, line 180, at commit 26de7be8

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selectGuardedArm()