feat: carry the byte offset and column in SyntaxError

Assisted-by: GLM 5.3 Flash
2026-09-21 23:55:58 +02:00
parent 3cc168f39a
commit 10d49fbe60
5 changed files with 120 additions and 17 deletions
@@ -51,6 +51,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  failure alike. `Valid(data)` reports whether a document parses, nil on
  success and the parse error on failure, the library call the `-validate`
  mode of interpres-decode is built on.
+- `SyntaxError` carries the byte `Offset` the scan stopped at and the 1-based
+  `Column` on the line, beside the line it always had, and `SourceLine(src)`
+  renders that line with a caret under the position, for messages shown under
+  the input. An input that is not valid UTF-8 names the offset of the first
+  invalid byte in its message. The new fields are additive: a `SyntaxError`
+  built from a line and a message alone is unchanged.
 - `Decoder.UseNumber()` decodes the integers and floats of the document into
  `Number`, which carries the literal the document wrote, so `0x1f`, `1_000`,
  `+1.0` and `inf` survive a round trip with their spelling instead of the