comments improved

src/frontend/inp.c

@@ -327,15 +327,18 @@ inp_spsource(FILE *fp, bool comfile, char *filename, bool intfile)
     tfree(dir_name);
 
     /* if nothing came back from inp_readall, just close fp and return to caller */
-    if (!deck) {        /* MW. We must close fp always when returning */
+    if (!deck) {
         if (!intfile)
             fclose(fp);
         return;
     }
 
     if (!comfile) {
+        /* Extract the .option lines from the deck into 'options',
+           and remove them from the deck. */
         options = inp_getopts(deck);
 
+        /* copy a deck before subckt substitution. */
         realdeck = inp_deckcopy(deck);
 
         /* Save the title before INPgetTitle gets it. */

src/frontend/inpcom.c

@@ -548,7 +548,7 @@ inp_readall(FILE *fp, char *dir_name, bool comfile, bool intfile)
         /* get max. line length and number of lines in input deck,
            and renumber the lines,
            count the number of '{' per line as an upper estimate of the number
-           of parameter substitutions in a line*/
+           of parameter substitutions in a line */
         dynmaxline = 0;
         max_line_length = 0;
         no_braces = 0;
@@ -1320,6 +1320,15 @@ inp_chk_for_multi_in_vcvs(struct line *c, int *line_number)
 }
 
 
+/* If ngspice is started with option -a, then variable 'autorun'
+ *   will be set and the following function scans the deck.
+ * If 'run' is not found, a .control section will be added:
+ *   .control
+ *   run
+ *   op              ; if .op is found
+ *   write rawfile   ; if rawfile given
+ *   .endc
+ */
 static void
 inp_add_control_section(struct line *deck, int *line_number)
 {
@@ -1386,8 +1395,8 @@ inp_add_control_section(struct line *deck, int *line_number)
 }
 
 
-// look for shell-style end-of-line continuation '\\'
-
+/* overwrite shell-style end-of-line continuation '\\' with spaces,
+ *   and return TRUE when found */
 static bool
 chk_for_line_continuation(char *line)
 {
@@ -5760,6 +5769,10 @@ inp_poly_err(struct line *card)
 #endif
 
 
+/* Used for debugging. You may add
+ *   tprint(working);
+ * somewhere in function inp_readall() of this file to have
+ *   a printout of the actual deck written to file "tprint-out.txt" */
 void
 tprint(struct line *t)
 {
@@ -6021,6 +6034,8 @@ inp_fix_temper_in_param(struct line *deck)
 }
 
 
+/* append "()" to each 'identifier' in 'curr_line',
+ *   unless already there */
 static char *
 inp_functionalise_identifier(char *curr_line, char *identifier)
 {

src/frontend/subckt.c

@@ -242,9 +242,9 @@ inp_subcktexpand(struct line *deck) {
             if (ciprefix(".model", c->li_line))
                 nupa_scan(c->li_line, c->li_linenum, FALSE);
         }
+        /* now copy instances */
         for (c = deck; c; c = c->li_next)  /* first Numparam pass */
             c->li_line = nupa_copy(c->li_line, c->li_linenum);
-        /* now copy instances */
 
 #ifdef TRACE
         fprintf(stderr, "Numparams transformed deck:\n");

src/misc/string.c

@@ -40,6 +40,10 @@ copy(const char *str)
     return(p);
 }
 
+
+/* copy a substring, from 'str' to 'end'
+ *   including *str, excluding *end
+ */
 char *
 copy_substring(const char *str, const char *end)
 {