Build final Perl program from `incdec.pm`

Build an intermediary Perl file that includes the extra lines that call
`incdec()`. This whole file should be included in the final Bash
function `perl -e` call.

2 files changed, 13 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 667ff7e..b1a3109 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,9 @@
 .PHONY: test
 test:
 	prove -v
+
+
+incdec.pl: incdec.pl.m4 incdec.pm
+	sed -n '/sub incdec {/,/^}/p' incdec.pm > incdec.sub.pl
+	m4 $< > $@
+	rm incdec.sub.pl
diff --git a/incdec.pl.m4 b/incdec.pl.m4
new file mode 100644
index 0000000..03fb905
--- /dev/null
+++ b/incdec.pl.m4
@@ -0,0 +1,7 @@
+use strict;
+use warnings;
+
+include(`incdec.sub.pl')dnl
+
+my $output = incdec($line, $increment_by, $point_position, $backward);
+print $output;