From 4e3ef6118691fce8dcdcd8214c5866a7e5a8c8f3 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 8 May 2022 08:19:56 -0700
Subject: Implement -f option: commands from file.

---
 pw.1 | 23 +++++++++++++++++++++++
 pw.c | 41 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/pw.1 b/pw.1
index fcb4709..6785564 100644
--- a/pw.1
+++ b/pw.1
@@ -856,6 +856,29 @@ sets a head-referenced trigger for the pattern
 .B ^Failed
 matching against line 3 of the FIFO.
 
+.IP "\fB-f\fP \fIfile\fP"
+Read colon and trigger commands from
+.I file
+and execute them.
+
+Each line of
+.I file
+must contain either a command in the same form as the argument of the
+.B -e
+option, or else a comment indicated by the first character being
+.B #
+(hash).
+
+If any line is diagnosed as erroneous, a diagnostic is issued
+and execution continues. In this case,
+.I pw
+will terminate unsuccessfully after
+.I file
+is read.
+
+Command lines with leading whitespace are invalid, and trailing whitespace
+counts as a command character (for example, as a constituent of a pattern),
+
 .SH ENVIRONMENT
 
 .I pw
diff --git a/pw.c b/pw.c
index e878823..cfc4d71 100644
--- a/pw.c
+++ b/pw.c
@@ -269,6 +269,18 @@ static char *addchesc(char *line, int ch)
   return line;
 }
 
+static char *getln(FILE *stream)
+{
+  for (char *line = 0;;) {
+    int ch = getc(stream);
+    if (ch == EOF)
+      return line;
+    if (ch == '\n')
+      return dsensure(line);
+    line = addchesc(line, ch);
+  }
+}
+
 static void usage(void)
 {
   fprintf(stderr,
@@ -283,7 +295,8 @@ static void usage(void)
           "-g [!]pattern   add pattern to grep stack; ! inverts\n"
           "-m integer      specify maixmum line length\n"
           "-p values       set display parameters\n"
-          "-e command      execute :, / or ? command\n\n"
+          "-e command      execute : /  ? command\n"
+          "-f file         execute : /  ? commands from file\n\n"
           "<command> represents an arbitrary command that generates the\n"
           "output to be monitored by %s.\n\n"
           "Standard input must be redirected; it cannot be the same device\n"
@@ -994,7 +1007,7 @@ int main(int argc, char **argv)
     }
   }
 
-  while ((opt = getopt(argc, argv, "n:i:l:dEBg:q:m:p:e:")) != -1) {
+  while ((opt = getopt(argc, argv, "n:i:l:dEBg:q:m:p:e:f:")) != -1) {
     switch (opt) {
     case 'n':
       {
@@ -1121,7 +1134,31 @@ int main(int argc, char **argv)
           error("-%c option: %s: %s\n", opt, optarg, pw.cmdbuf);
           return EXIT_FAILURE;
         }
+      }
+      break;
+    case 'f':
+      {
+        FILE *f = fopen(optarg, "r");
+        long lino = 1;
+        int errors = 0;
+        char *line;
+        if (f == 0) {
+          error("-%c option: unable to open %s\n", opt, optarg);
+          return EXIT_FAILURE;
+        }
+        for (; (line = getln(f)) != 0; lino++) {
+          if (line[0] == '#')
+            continue;
+          if (batchexe(&pw, line, pw.cmdbuf, cmdsize) == exec_failed) {
+            error("%s:%ld: %s\n", optarg, lino, pw.cmdbuf);
+            errors = 1;
+          }
+          dsdrop(line);
+        }
+        fclose(f);
+        if (errors) {
           return EXIT_FAILURE;
+          dsdrop(line);
         }
       }
       break;
-- 
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