[groff] 33/33: [eqn]: Clear line number when it becomes nonsense.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit c2e894cf5b42cfdaae48f03476fee24a6103f9c9
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sun Oct 16 14:23:26 2022 -0500

    [eqn]: Clear line number when it becomes nonsense.
    
    * src/preproc/eqn/lex.cpp (get_delimited_text): Clear line number when
      hitting EOF.
    
    * src/preproc/eqn/main.cpp: Revise end-of-file handling.  Clear line
      number upon reaching EOF so that we don't report a nonsense value one
      greater than the number of lines in the input file.
    
      (read_line): Boolify.  Make static (local linkage only), since it has
      no external callers.  Introduce new Boolean variable `is_end_of_file`.
      Clear `current_lineno` if EOF, and increment it otherwise.
    
      (do_file, main): Clarify diagnostic messages.
---
 ChangeLog                | 13 +++++++++++++
 src/preproc/eqn/lex.cpp  |  2 ++
 src/preproc/eqn/main.cpp | 16 ++++++++++------
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 97061669f..b57357021 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2022-10-15  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/preproc/eqn/lex.cpp (get_delimited_text): Clear line
+       number when hitting EOF.
+       * src/preproc/eqn/main.cpp: Revise end-of-file handling.  Clear
+       line number upon reaching EOF so that we don't report a nonsense
+       value one greater than the number of lines in the input file.
+       (read_line): Boolify.  Make static (local linkage only), since
+       it has no external callers.  Introduce new Boolean variable
+       `is_end_of_file`.  Clear `current_lineno` if EOF, and increment
+       it otherwise.
+       (do_file, main): Clarify diagnostic messages.
+
 2022-10-15  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [eqn]: Improve diagnostics involving unprintable characters.
diff --git a/src/preproc/eqn/lex.cpp b/src/preproc/eqn/lex.cpp
index 2770b69e0..afca8e6f8 100644
--- a/src/preproc/eqn/lex.cpp
+++ b/src/preproc/eqn/lex.cpp
@@ -710,6 +710,7 @@ void get_delimited_text()
     start = get_char();
   token_buffer.clear();
   if (start == EOF) {
+    current_lineno = 0;
     if (got_location)
       error_with_file_and_line(filename, lineno,
                               "end of input while defining macro");
@@ -720,6 +721,7 @@ void get_delimited_text()
   for (;;) {
     int c = get_char();
     if (c == EOF) {
+      current_lineno = 0;
       if (got_location)
        error_with_file_and_line(filename, lineno,
                                 "end of input while defining macro");
diff --git a/src/preproc/eqn/main.cpp b/src/preproc/eqn/main.cpp
index 536f256a9..eee83d435 100644
--- a/src/preproc/eqn/main.cpp
+++ b/src/preproc/eqn/main.cpp
@@ -76,7 +76,7 @@ static const char *input_char_description(int c)
   return buf;
 }
 
-int read_line(FILE *fp, string *p)
+static bool read_line(FILE *fp, string *p)
 {
   p->clear();
   int c = -1;
@@ -88,8 +88,12 @@ int read_line(FILE *fp, string *p)
     if (c == '\n')
       break;
   }
-  current_lineno++;
-  return p->length() > 0;
+  bool is_end_of_file = (p->length() > 0);
+  if (is_end_of_file)
+    current_lineno++;
+  else
+    current_lineno = 0;
+  return is_end_of_file;
 }
 
 void do_file(FILE *fp, const char *filename)
@@ -132,7 +136,7 @@ void do_file(FILE *fp, const char *filename)
          else if (linebuf[2] == 'Q' && linebuf.length() > 3
                   && (linebuf[3] == ' ' || linebuf[3] == '\n'
                       || compatible_flag))
-           fatal("nested .EQ");
+           fatal("equations cannot be nested (.EQ within .EQ)");
        }
        str += linebuf;
       }
@@ -451,7 +455,7 @@ int main(int argc, char **argv)
        errno = 0;
        FILE *fp = fopen(argv[i], "r");
        if (!fp)
-         fatal("can't open '%1': %2", argv[i], strerror(errno));
+         fatal("unable to open '%1': %2", argv[i], strerror(errno));
        else {
          do_file(fp, argv[i]);
          if (fclose(fp) < 0)
@@ -459,7 +463,7 @@ int main(int argc, char **argv)
        }
       }
   if (ferror(stdout))
-    fatal("error status on standard output stream");
+    fatal("standard output stream is in an error state");
   if (fflush(stdout) < 0)
     fatal("unable to flush standard output stream: %1",
          strerror(errno));