Lazy quantifiers and replacement

Appending ? to a quantifier creates a lazy quantifier matching the fewest characters possible. The replace operation substitutes matches, substituting group placeholders like $1.

Mental Model: Minimal Expansion and $N Substitution

• <.+?> over "<a><b>": stops at "<a>" rather than spanning to the final >.
• Template "[$1]" injects group 1's capture "a" -> "[a]".

Your Goal in this Stage

Implement lazy quantifiers and op: "replace" with all: true and group backreferences.

Input Format

{
  "op": "replace",
  "pattern": "<(.+?)>",
  "text": "<a><b>",
  "replacement": "[$1]",
  "all": true
}

Output Format

{
  "text": "[a][b]"
}

Step-by-Step Implementation Guide

1. Lazy quantifiers: Try minimum repetitions first, growing only when required.
2. String replacement: Interpolate $1, $2 with group captures.
3. Global replacement: Repeat across text when all: true.
4. Emit output: Print JSON object.

Acceptance Criteria

• ✅ Minimal matching with lazy quantifiers.
• ✅ Replaces capture references $1, $2.

Multiline examples are formatted for readability. Emit compact JSON without optional spaces, with properties in the order shown by the output examples, and a final newline. Keep logs off stdout. Tests compare exact text. Invalid inputs use stderr containing error, empty stdout, and exit 1. Valid inputs exit 0. Serialize integer results as JSON integers.

$0 means the complete match; $1 through $9 mean numbered captures. A reference to a nonexistent group remains literal: (a) on a with $1-$9 produces a-$9. An existing optional group that did not participate contributes an empty string. With all: false, replace only the first match; with all: true, replace non-overlapping matches from left to right. Advance one character after an empty match to avoid an infinite loop.