Pass exec result to constraint in Matcher

[Pisces] / string.js

diff --git a/string.js b/string.js
index 8c858cd66a527b56c8a0d591a75d77e1f5134b60..28412fc98b8854b9b26f248c5e8b8ae98526d033 100644 (file)
--- a/string.js
+++ b/string.js
@@ -65,11 +65,11 @@ export const {
      * A name for the matcher may be provided as the second argument.
      *
      * A callable constraint on acceptable inputs may be provided as a
-     * third argument. If provided, it will be called with two
+     * third argument. If provided, it will be called with three
      * arguments whenever a match appears successful: first, the string
-     * being matched, and second, the Matcher object itself. If the
-     * return value of this call is falsey, then the match will be
-     * considered a failure.
+     * being matched, second, the match result, and third, the Matcher
+     * object itself. If the return value of this call is falsey, then
+     * the match will be considered a failure.
      *
      * ☡ If the provided source regular expression uses nongreedy
      * quantifiers, it may not match the whole string even if a match
@@ -89,8 +89,9 @@ export const {
             // at a match matches the whole string and passes the
             // provided constraint (if present).
             regExp.lastIndex = 0;
-            return call(reExec, regExp, [$])?.[0] === $ &&
-              (constraint === null || constraint($, this));
+            const result = call(reExec, regExp, [$]);
+            return result?.[0] === $ &&
+              (constraint === null || constraint($, result, this));
           }
         },
       );
@@ -148,6 +149,10 @@ export const {
      *
      * Matchers only match if they can match the entire value on the
      * first attempt.
+     *
+     * ☡ The match result returned by this method will be the same as
+     * that passed to the constraint function—and may have been
+     * modified by said function prior to being returned.
      */
     exec($) {
       const regExp = this.#regExp;
@@ -157,7 +162,7 @@ export const {
       const result = call(reExec, regExp, [string]);
       if (
         result?.[0] === string &&
-        (constraint === null || constraint(string, this))
+        (constraint === null || constraint(string, result, this))
       ) {
         // The entire string was matched and the constraint, if
         // present, returned a truthy value.