feat(lib): add experimental _EXP_STRING backed by std::string

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

6 files changed, 30 insertions, 0 deletions

diff --git a/tests/i/class-copy/notes.md b/tests/i/class-copy/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+Each completed default/copy construction increments Live; only copy construction increments Copies. Pass destroys its independent modified copy. Make copies its local into the result before destroying the local. Forward transfers that result. Discarded results, temporary receivers and constructor-bound results are destroyed at statement end. A later argument throwing destroys the already-created argument before entering CATCH. At the final count, nine copies have completed and only A, B and C remain live; reverse destruction removes values 8, 1 and 1. Remaining is zero. This is the class lifetime extension.
diff --git a/tests/i/escape-sequences/notes.md b/tests/i/escape-sequences/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+Simple escapes produce a literal quote, backslash and question mark. Octal 101 and hexadecimal 42 add A and B after the leading A; Unicode escapes encode the displayed accented letter and emoji. Escaped CHAR byte values are 10, 9 and 255. Built-in STRING stops at the embedded NUL.
diff --git a/tests/i/extern-cc-runtime/notes.md b/tests/i/extern-cc-runtime/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+A C++ string starts with 4096 x bytes and appends the three digits 123, giving 4099. The second EXTERN function catches and rethrows invalid_argument; pseudocode catches it once. These are C++ object and exception extensions.
diff --git a/tests/i/library-lines/notes.md b/tests/i/library-lines/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+User calls on lines 3, 8 and 13 enter nested library array access, an array-argument contract and a close of an unopened file. The declaration on line 18 automatically invokes a library constructor that divides by zero. Each error uses that user line and is caught. These are library and exception extensions.
diff --git a/tests/i/operator-assign/notes.md b/tests/i/operator-assign/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+Assignments copy 3 into B, self-assign 3, then copy the returned 7. C_STRING assignment sets A to length 5 without a copy trace. Record-field, array-element and dereferenced assignments trace 7, 5 and 7. Final fields are 7, 7, 7 and 5. This is the member assignment extension.
diff --git a/tests/i/underscore-identifiers/notes.md b/tests/i/underscore-identifiers/notes.md
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+# Trace notes
+
+Review status: pending human review.
+
+The underscore-prefixed class holds an INTEGER. The underscore-prefixed function adds one to 41 and the underscore-prefixed variable receives 42. This is a compiler identifier extension.