X-Git-Url: https://git.distorted.org.uk/~mdw/runlisp/blobdiff_plain/f50ecbe185f8866970ab62157b2e45bf613907d2..68f84445eae7a1267a0ef2592e3cb6725544a7cd:/lib.c

diff --git a/lib.c b/lib.c
index 251d932..c844997 100644
--- a/lib.c
+++ b/lib.c
@@ -51,7 +51,7 @@ void set_progname(const char *prog)
   const char *p;
 
   p = strrchr(prog, '/');
-  progname = p ? p + 1 : progname;
+  progname = p ? p + 1 : prog;
 }
 
 /* Report an error or warning in Unix style, given a captured argument
@@ -377,7 +377,7 @@ void argv_prependl(struct argv *av, ...)
 /* Return nonzero if the AN-byte string A is strictly precedes the BN-byte
  * string B in a lexicographic ordering.
  *
- * All comparisons of keys is handled by this function.
+ * All comparison of keys is handled by this function.
  */
 static int str_lt(const char *a, size_t an, const char *b, size_t bn)
 {
@@ -515,7 +515,7 @@ void treap_insert(struct treap *t, const struct treap_path *p,
      *		  /   \			      /   \
      *		X       Y		    Y	    Z
      *
-     * On the other hand, if we ere planning to hook N as the right subtree
+     * On the other hand, if we were planning to hook N as the right subtree
      * of U, then we do the opposite rotation:
      *
      *		    |				|
@@ -735,7 +735,7 @@ static void check_subtree(struct treap_node *n, unsigned maxwt,
   if (khi) assert(STRCMP(n->k, <, khi));
 
   /* Check the left subtree.  Node weights must be bounded above by our own
-   * weight.  And everykey in the left subtree must be smaller than our
+   * weight.  And every key in the left subtree must be smaller than our
    * current key.  We propagate the lower bound.
    */
   if (n->left) check_subtree(n->left, n->wt, klo, n->k);
@@ -1251,7 +1251,7 @@ void config_read_env(struct config *conf, struct config_section *sect)
  *
  * This only keeps track of the immutable parameters for the substitution
  * task: stuff which changes (flags, filtering state, cursor position) is
- *	 maintained separately.
+ * maintained separately.
  */
 struct subst {
   struct config *config;		/* configuration state */
@@ -1336,8 +1336,9 @@ static void filter_string(const char *p, const char *l,
 
 /* Scan and resolve a `[SECT:]VAR' specifier at P.
  *
- * Return the address of the next character following the specifier.  L is a
- * limit on the region of the buffer that we should process; SB is the
+ * Return the address of the next character following the specifier; and set
+ * *VAR_OUT to point to the variable we found, or null if it's not there.  L
+ * is a limit on the region of the buffer that we should process; SB is the
  * substitution state which provides the home section if none is given
  * explicitly; FILE and LINE are the source location to blame for problems.
  */
@@ -1379,7 +1380,12 @@ static const char *subst(const char *p, const char *l,
   size_t n;
 
   /* It would be best if we could process literal text at high speed.  To
-   * this end,
+   * this end, we have a table, indexed by the low-order bits of F, to tell
+   * us which special characters we need to stop at.  This way, we can use
+   * `strcspn' to skip over literal text and stop at the next character which
+   * needs special handling.  Entries in this table with a null pointer
+   * correspond to impossible flag settings: notably, `SF_QUOT' can only be
+   * set when `SF_SUBST' is also set.
    */
   static const char *const delimtab[] = {
 
@@ -1391,26 +1397,27 @@ static const char *subst(const char *p, const char *l,
 					 * `SF_QUOT' */
 #define DELIM "|}"			/* end delimiters of `SF_SUBEXPR' */
 
-    ESCAPE,
-    ESCAPE	       WORDSEP,
-    0,
-    ESCAPE	       QUOT,
-    ESCAPE	 SUBST,
-    ESCAPE	 SUBST WORDSEP,
-    0,
-    ESCAPE	 SUBST QUOT,
-    ESCAPE DELIM,
-    ESCAPE DELIM       WORDSEP,
-    0,
-    ESCAPE DELIM       QUOT,
-    ESCAPE DELIM SUBST,
-    ESCAPE DELIM SUBST WORDSEP,
-    0,
-    ESCAPE DELIM SUBST QUOT
-
-#undef COMMON
+    ESCAPE,				/* --- */
+    ESCAPE	       WORDSEP,		/* SPLIT */
+    0,					/*	   QUOT */
+    ESCAPE	       QUOT,		/* SPLIT | QUOT */
+    ESCAPE	 SUBST,			/*		  SUBST */
+    ESCAPE	 SUBST WORDSEP,		/* SPLIT |	  SUBST */
+    0,					/*	   QUOT | SUBST */
+    ESCAPE	 SUBST QUOT,		/* SPLIT | QUOT | SUBST */
+    ESCAPE DELIM,			/*			  SUBEXPR */
+    ESCAPE DELIM       WORDSEP,		/* SPLIT |		  SUBEXPR */
+    0,					/*	   QUOT |	  SUBEXPR */
+    ESCAPE DELIM       QUOT,		/* SPLIT | QUOT |	  SUBEXPR */
+    ESCAPE DELIM SUBST,			/*		  SUBST | SUBEXPR */
+    ESCAPE DELIM SUBST WORDSEP,		/* SPLIT |	  SUBST | SUBEXPR */
+    0,					/*	   QUOT | SUBST | SUBEXPR */
+    ESCAPE DELIM SUBST QUOT		/* SPLIT | QUOT | SUBST | SUBEXPR */
+
+#undef ESCAPE
+#undef SUBST
 #undef WORDSEP
-#undef SQUOT
+#undef QUOT
 #undef DELIM
   };
 
@@ -1451,12 +1458,12 @@ static const char *subst(const char *p, const char *l,
        * to it.
        */
 
-      /* If there's no next charact3er then we should be upset. */
+      /* If there's no next character then we should be upset. */
       p++; if (p >= l) lose("%s:%u: unfinished `\\' escape", file, line);
 
       if (!(f&SF_SKIP)) {
 
-	/* If this is a double quote or backslash then check DFLT to see if
+	/* If this is a double quote or backslash then check QFILT to see if
 	 * it needs escaping.
 	 */
 	if (qfilt && (*p == '"' || *p == '\\'))
@@ -1583,13 +1590,13 @@ static const char *subst(const char *p, const char *l,
 	       * toothpick, so now we need Q + (Q + 1) = 2 Q + 1 toothpicks.
 	       *
 	       * Calculate this here rather than at each point toothpicks
-	       * needs to be deployed.
+	       * need to be deployed.
 	       */
 
 	      subqfilt = 2*subqfilt + 1;
 
 	    else if (t - p == 1 && *p == 'l')
-	      /* `u' -- convert to uppercase.
+	      /* `l' -- convert to lowercase.
 	       *
 	       * If a case conversion is already set, then that will override
 	       * whatever we do here, so don't bother.