+ +
+
+

Recording where fragments of text originally came from.

+ +

§1. Inter code sometimes needs to contain fragments of not-yet-parsed Inform 6 +syntax code, in the form of SPLAT_IST and INSERT_IST instructions. In order +for it to be possible to relate errors in those fragments to the original text +files they came from, we need to record their "provenance". +

+ +

This is only a wrapper for saying something like "line 17 in whatever.txt". +Line numbers count from 1 at the top of a text file. +

+ +
+typedef struct text_provenance {
+    struct text_stream *textual_filename;
+    int line_number;
+} text_provenance;
+
+
  • The structure text_provenance is private to this section.
+

§2. This provides a "don't know, or, it didn't come from a text file, I made it up" +value: +

+ +
+text_provenance Provenance::nowhere(void) {
+    text_provenance nowhere;
+    nowhere.textual_filename = NULL;
+    nowhere.line_number = 0;
+    return nowhere;
+}
+
+int Provenance::is_somewhere(text_provenance where) {
+    if (Str::len(where.textual_filename) > 0) return TRUE;
+    return FALSE;
+}
+
+

§3. Composing: +

+ +
+text_provenance Provenance::at_file_and_line(text_stream *file, int line) {
+    text_provenance somewhere;
+    somewhere.textual_filename = Str::duplicate(file);
+    somewhere.line_number = line;
+    return somewhere;
+}
+
+

§4. Decomposing: +

+ +
+int Provenance::get_line(text_provenance where) {
+    if (Provenance::is_somewhere(where)) return where.line_number;
+    return 0;
+}
+
+filename *Provenance::get_filename(text_provenance where) {
+    if (Provenance::is_somewhere(where))
+        return Filenames::from_text(where.textual_filename);
+    return NULL;
+}
+
+

§5. Altering in place: +

+ +
+void Provenance::set_line(text_provenance *where, int lc) {
+    if ((where) && (Provenance::is_somewhere(*where)))
+        where->line_number = lc;
+}
+
+

§6. Writing to text: +

+ +
+void Provenance::write(OUTPUT_STREAM, text_provenance at) {
+    if (Provenance::is_somewhere(at)) {
+        TextualInter::write_text(OUT, at.textual_filename);
+        WRITE(" %d", at.line_number);
+    } else {
+        WRITE("<nowhere>");
+    }
+}
+
+ + +