From: Simon Ruderich <simon@ruderich.org>
Date: Sun, 1 Mar 2009 15:19:29 +0000 (+0100)
Subject: lib.sh: m4() define useful macros.
X-Git-Url: https://ruderich.org/simon/gitweb/?a=commitdiff_plain;h=8c731331a353d82adc61a81bd3cb92e79f3c2dc8;p=config%2Fdotfiles.git

lib.sh: m4() define useful macros.

At the moment only IF and FI are defined which can be used for easy checking
of variables. They use the ifelse() macro.
---

diff --git a/lib.sh b/lib.sh
index ea61359..88b7b98 100644
--- a/lib.sh
+++ b/lib.sh
@@ -73,6 +73,11 @@ link() {
 # to $1 with a warning at the beginning to not edit the generated file.
 #
 # All arguments (except the first which is the filename) are passed to m4.
+#
+# The following macros are defined: IF and FI. Example:
+#     IF(OS, debian)
+#         ...
+#     FI
 m4() {
     # First argument is file name.
     file=$1
@@ -88,7 +93,11 @@ m4() {
 
     # Process $1.m4 with m4 using the given options.
     echo "m4(): generating '$file' from '$file.m4' with options '$*'"
-    $m4 $* $file.m4 >> $file
+    # Add useful macros.
+    (echo "define(\`IF', \`ifelse(\`\$1', \`\$2',dnl')dnl
+define(\`FI', \`)dnl')dnl";
+        # Run the file (and the default macros) through m4.
+        cat $file.m4) | $m4 $* >> $file
 
     unset file
 }