Include "exitfail.h", "quotearg.h".

(EXPR_INVALID, EXPR_ERROR): New constants.
(nomoreargs, null, toarith, nextarg): Return bool, not int.
(syntax_error): New function, exiting with status 2.  Use it
insteading of printing "syntax error" ourselves.
(main): Initialize exit_failure to EXPR_ERROR.
Exit with EXPR_INVALID on syntax error (too few arguments).
(nextarg): Use strcmp, not strcoll; strcoll might return
an undesirable 0, or might fail.
(docolon, eval4, eval3): Exit with status 3 on invalid argument type
or other such error.
(eval2): Report an error if strcoll fails in a string comparison.

1 files changed, 72 insertions, 27 deletions

diff --git a/src/expr.c b/src/expr.c
index bfc8dc545..c7f81db3f 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -37,7 +37,9 @@
 #include "long-options.h"
 #include "error.h"
 #include "closeout.h"
+#include "exitfail.h"
 #include "inttostr.h"
+#include "quotearg.h"
 
 /* The official name of this program (e.g., no `g' prefix).  */
 #define PROGRAM_NAME "expr"
@@ -48,6 +50,18 @@
 #define NEW(Type) XMALLOC (Type, 1)
 #define OLD(x) free (x)
 
+/* Exit statuses.  */
+enum
+  {
+    /* Invalid expression: i.e., its form does not conform to the
+       grammar for expressions.  Our grammar is an extension of the
+       POSIX grammar.  */
+    EXPR_INVALID = 2,
+
+    /* Some other error occurred.  */
+    EXPR_ERROR
+  };
+
 /* The kinds of value we can have.  */
 enum valtype
 {
@@ -75,8 +89,8 @@ static char **args;
 char *program_name;
 
 static VALUE *eval (void);
-static int nomoreargs (void);
-static int null (VALUE *v);
+static bool nomoreargs (void);
+static bool null (VALUE *v);
 static void printv (VALUE *v);
 
 void
@@ -151,6 +165,13 @@ Pattern matches return the string matched between \\( and \\) or null; if\n\
   exit (status);
 }
 
+/* Report a syntax error and exit.  */
+static void
+syntax_error (void)
+{
+  error (EXPR_INVALID, 0, _("syntax error"));
+}
+
 int
 main (int argc, char **argv)
 {
@@ -162,6 +183,9 @@ main (int argc, char **argv)
   bindtextdomain (PACKAGE, LOCALEDIR);
   textdomain (PACKAGE);
 
+  /* Change the way library functions fail.  */
+  exit_failure = EXPR_ERROR;
+
   atexit (close_stdout);
 
   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
@@ -177,14 +201,14 @@ main (int argc, char **argv)
   if (argc <= 1)
     {
       error (0, 0, _("too few arguments"));
-      usage (EXIT_FAILURE);
+      usage (EXPR_INVALID);
     }
 
   args = argv + 1;
 
   v = eval ();
   if (!nomoreargs ())
-    error (2, 0, _("syntax error"));
+    syntax_error ();
   printv (v);
 
   exit (null (v));
@@ -249,9 +273,9 @@ printv (VALUE *v)
   puts (p);
 }
 
-/* Return nonzero if V is a null-string or zero-number.  */
+/* Return true if V is a null-string or zero-number.  */
 
-static int
+static bool
 null (VALUE *v)
 {
   switch (v->type)
@@ -285,19 +309,19 @@ tostring (VALUE *v)
     }
 }
 
-/* Coerce V to an integer value.  Return 1 on success, 0 on failure.  */
+/* Coerce V to an integer value.  Return true on success, false on failure.  */
 
-static int
+static bool
 toarith (VALUE *v)
 {
   intmax_t i;
-  int neg;
+  bool neg;
   char *cp;
 
   switch (v->type)
     {
     case integer:
-      return 1;
+      return true;
     case string:
       i = 0;
       cp = v->u.s;
@@ -310,14 +334,14 @@ toarith (VALUE *v)
 	  if (ISDIGIT (*cp))
 	    i = i * 10 + *cp - '0';
 	  else
-	    return 0;
+	    return false;
 	}
       while (*++cp);
 
       free (v->u.s);
       v->u.i = i * (neg ? -1 : 1);
       v->type = integer;
-      return 1;
+      return true;
     default:
       abort ();
     }
@@ -326,22 +350,22 @@ toarith (VALUE *v)
 /* Return nonzero and advance if the next token matches STR exactly.
    STR must not be NULL.  */
 
-static int
-nextarg (char *str)
+static bool
+nextarg (char const *str)
 {
   if (*args == NULL)
     return 0;
   else
     {
-      int r = strcoll (*args, str) == 0;
+      bool r = strcmp (*args, str) == 0;
       args += r;
       return r;
     }
 }
 
-/* Return nonzero if there no more tokens.  */
+/* Return true if there no more tokens.  */
 
-static int
+static bool
 nomoreargs (void)
 {
   return *args == 0;
@@ -399,7 +423,7 @@ of the basic regular expression is not portable; it is being ignored"),
   re_syntax_options = RE_SYNTAX_POSIX_BASIC;
   errmsg = re_compile_pattern (pv->u.s, len, &re_buffer);
   if (errmsg)
-    error (2, 0, "%s", errmsg);
+    error (EXPR_ERROR, 0, "%s", errmsg);
 
   matchlen = re_match (&re_buffer, sv->u.s, strlen (sv->u.s), 0, &re_regs);
   if (0 <= matchlen)
@@ -436,18 +460,18 @@ eval7 (void)
   trace ("eval7");
 #endif
   if (nomoreargs ())
-    error (2, 0, _("syntax error"));
+    syntax_error ();
 
   if (nextarg ("("))
     {
       v = eval ();
       if (!nextarg (")"))
-	error (2, 0, _("syntax error"));
+	syntax_error ();
       return v;
     }
 
   if (nextarg (")"))
-    error (2, 0, _("syntax error"));
+    syntax_error ();
 
   return str_value (*args++);
 }
@@ -469,7 +493,7 @@ eval6 (void)
   if (nextarg ("+"))
     {
       if (nomoreargs ())
-	error (2, 0, _("syntax error"));
+	syntax_error ();
       return str_value (*args++);
     }
   else if (nextarg ("length"))
@@ -584,13 +608,13 @@ eval4 (void)
 	return l;
       r = eval5 ();
       if (!toarith (l) || !toarith (r))
-	error (2, 0, _("non-numeric argument"));
+	error (EXPR_ERROR, 0, _("non-numeric argument"));
       if (fxn == multiply)
 	val = l->u.i * r->u.i;
       else
 	{
 	  if (r->u.i == 0)
-	    error (2, 0, _("division by zero"));
+	    error (EXPR_ERROR, 0, _("division by zero"));
 	  val = fxn == divide ? l->u.i / r->u.i : l->u.i % r->u.i;
 	}
       freev (l);
@@ -623,7 +647,7 @@ eval3 (void)
 	return l;
       r = eval4 ();
       if (!toarith (l) || !toarith (r))
-	error (2, 0, _("non-numeric argument"));
+	error (EXPR_ERROR, 0, _("non-numeric argument"));
       val = fxn == plus ? l->u.i + r->u.i : l->u.i - r->u.i;
       freev (l);
       freev (r);
@@ -642,9 +666,11 @@ eval2 (void)
   {
     less_than, less_equal, equal, not_equal, greater_equal, greater_than
   } fxn;
-  int val;
+  bool val;
   intmax_t lval;
   intmax_t rval;
+  int collation_errno;
+  char *collation_arg1;
 
 #ifdef EVAL_TRACE
   trace ("eval2");
@@ -669,13 +695,31 @@ eval2 (void)
       r = eval3 ();
       tostring (l);
       tostring (r);
-      lval = strcoll (l->u.s, r->u.s);
+
+      /* Save the first arg to strcoll, in case we need its value for
+	 a diagnostic later.  This is needed because 'toarith' might
+	 free the first arg.  */
+      collation_arg1 = xstrdup (l->u.s);
+
+      errno = 0;
+      lval = strcoll (collation_arg1, r->u.s);
+      collation_errno = errno;
       rval = 0;
       if (toarith (l) && toarith (r))
 	{
 	  lval = l->u.i;
 	  rval = r->u.i;
 	}
+      else if (collation_errno)
+	{
+	  error (0, collation_errno, _("string comparison failed"));
+	  error (0, 0, _("Set LC_ALL='C' to work around the problem."));
+	  error (EXPR_ERROR, 0,
+		 _("The strings compared were %s and %s."),
+		 quotearg_n_style (0, locale_quoting_style, collation_arg1),
+		 quotearg_n_style (1, locale_quoting_style, r->u.s));
+	}
+
       switch (fxn)
 	{
 	case less_than:     val = (lval <  rval); break;
@@ -688,6 +732,7 @@ eval2 (void)
 	}
       freev (l);
       freev (r);
+      free (collation_arg1);
       l = int_value (val);
     }
 }