FA-173 / Parsing / Member archive

An escaped separator becomes a field boundary · case 03

An escaped pipe splits a field, or an even run of escape characters hides a real separator.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

Split a pipe-delimited string. Only backslash-pipe and backslash-backslash are legal escapes. Preserve empty fields; reject incomplete or unknown escapes by returning None.

Why this case matters

Small transport and configuration grammars often need both literal separators and literal escape characters; checking only the previous character loses this distinction.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
literal escaped separator	`["fieldfieldfield\\", "inside", "tail"]`	`["fieldfieldfield\|inside", "tail"]`	Failed

MEMBER ARCHIVE

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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