+ works as a filter, now!

- I have a feeling I could have used strtok, but the
  2 functions I added are really small, so it shouldn't
  be a big deal.  (They were just laying around, and I
  wanted to use them, again).

1 files changed, 51 insertions, 6 deletions

diff --git a/math.c b/math.c
index 18af3534a..621b5c9b0 100644
--- a/math.c
+++ b/math.c
@@ -1,5 +1,6 @@
 /* vi: set sw=4 ts=4: */
 #include "internal.h"
+#include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -131,14 +132,58 @@ static void stack_machine(const char *argument)
         exit(-1);
 }
 
+/* return pointer to next token in buffer and set *buffer to one char
+ * past the end of the above mentioned token 
+ */
+static char *get_token(char **buffer)
+{
+        char *start   = NULL;
+        char *current = *buffer;
+
+        while (isspace(*current)) { current++; }
+        if (*current != 0) {
+                start = current;
+                while (!isspace(*current) && current != 0) { current++; }
+                *buffer = current;
+        }
+        return start;
+}
+
+/* In Perl one might say, scalar m|\s*(\S+)\s*|g */
+static int number_of_tokens(char *buffer)
+{
+        int   i = 0;
+        char *b = buffer;
+        while (get_token(&b)) { i++; }
+        return i;
+}
+
 int math_main(int argc, char **argv)
 {
-        if (argc <= 1 || *argv[1]=='-')
-                usage(math_usage);
-        while (argc >= 2) {
-                stack_machine(argv[1]);
-                argv++;
-                argc--;
+        /* take stuff from stdin if no args are given */
+        if (argc <= 1) {
+                int i, len;
+                char *line   = NULL;
+                char *cursor = NULL;
+                char *token  = NULL;
+                while ((line = cstring_lineFromFile(stdin))) {
+                        cursor = line;
+                        len = number_of_tokens(line);
+                        for (i = 0; i < len; i++) {
+                                token = get_token(&cursor);
+                                *cursor++ = 0;
+                                stack_machine(token);
+                        }
+                        free(line);
+                }
+        } else {
+                if (*argv[1]=='-')
+                        usage(math_usage);
+                while (argc >= 2) {
+                        stack_machine(argv[1]);
+                        argv++;
+                        argc--;
+                }
         }
         stack_machine(0);
         exit( TRUE);