From b94c199f29ba6223127dfb5c2becda9176e95c9c Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Mon, 5 Sep 2016 00:26:46 +1200
Subject: Add mftl(1df)

---
 .gitignore        |  1 +
 Makefile          |  6 ++++--
 README.markdown   |  1 +
 bin/mftl.awk      | 38 ++++++++++++++++++++++++++++++++++++++
 man/man1/mftl.1df | 30 ++++++++++++++++++++++++++++++
 5 files changed, 74 insertions(+), 2 deletions(-)
 create mode 100644 bin/mftl.awk
 create mode 100644 man/man1/mftl.1df

diff --git a/.gitignore b/.gitignore
index a8e2f9bb..bab3eb65 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 bin/han
 bin/mean
 bin/med
+bin/mftl
 bin/mode
 bin/rfct
 bin/rndi
diff --git a/Makefile b/Makefile
index 5fb1de75..98dd0baf 100644
--- a/Makefile
+++ b/Makefile
@@ -69,6 +69,7 @@ SENDMAIL := msmtp
 all : bin/han \
 	bin/mean \
 	bin/med \
+	bin/mftl \
 	bin/mode \
 	bin/rfct \
 	bin/rndi \
@@ -86,6 +87,7 @@ clean distclean :
 		bin/han \
 		bin/mean \
 		bin/med \
+		bin/mftl \
 		bin/mode \
 		bin/rfct \
 		bin/rndi \
@@ -177,8 +179,8 @@ install-bash-completion : install-bash
 	install -pm 0644 -- bash/bash_completion "$(HOME)"/.config/bash_completion
 	install -pm 0644 -- bash/bash_completion.d/* "$(HOME)"/.bash_completion.d
 
-install-bin : bin/han bin/sd2u bin/su2d bin/mean bin/med bin/mode \
-	bin/tot bin/unf check-bin install-bin-man
+install-bin : bin/han bin/sd2u bin/su2d bin/mean bin/med bin/mftl \
+	bin/mode bin/tot bin/unf check-bin install-bin-man
 	install -m 0755 -d -- "$(HOME)"/.local/bin
 	for name in bin/* ; do \
 		[ -x "$$name" ] || continue ; \
diff --git a/README.markdown b/README.markdown
index 36d689cf..2bc94c08 100644
--- a/README.markdown
+++ b/README.markdown
@@ -433,6 +433,7 @@ Installed by the `install-bin` target:
     it exits with success or failure. Good for quick tests.
 *   `mean(1df)` prints the mean of a list of integers.
 *   `med(1df)` prints the median of a list of integers.
+*   `mftl(1df)` finds usable-looking targets in Makefiles.
 *   `mode(1df)` prints the first encountered mode of a list of integers.
 *   `mkcp(1df)` creates a directory and copies preceding arguments into it.
 *   `mkmv(1df)` creates a directory and moves preceding arguments into it.
diff --git a/bin/mftl.awk b/bin/mftl.awk
new file mode 100644
index 00000000..c6d65409
--- /dev/null
+++ b/bin/mftl.awk
@@ -0,0 +1,38 @@
+# Try to find the targets in a Makefile that look like they're targets the user
+# could be reasonably expected to call directly
+
+# Separators are space, tab, or colon
+BEGIN {
+    FS = "[ \t:]"
+}
+
+# Skip comments
+/^#/ { next }
+
+# Join backslash-broken lines
+/\\$/ {
+    sub(/\\$/, "")
+    line = line $0 
+    next
+}
+{
+    $0 = line $0
+    line = ""
+}
+
+# Check lines matching expected "targets:dependencies" format
+/^[a-zA-Z0-9][a-zA-Z0-9 \t_-]+:([^=]|$)/ {
+
+    # Iterate through the targets that don't look like substitutions or
+    # inference rules and stack them up into an array's keys to keep them
+    # unique; this probably needs refinement
+    for (i=0; i<NF; i++)
+        if ($i ~ /^[a-zA-Z0-9][a-zA-Z0-9./_-]*$/)
+            ats[$i]
+}
+
+# Print unique determined targets, sorted
+END {
+    for (t in ats)
+        print t | "sort"
+}
diff --git a/man/man1/mftl.1df b/man/man1/mftl.1df
new file mode 100644
index 00000000..efb2b486
--- /dev/null
+++ b/man/man1/mftl.1df
@@ -0,0 +1,30 @@
+.TH MFTL 1df "September 2016" "Manual page for mftl"
+.SH NAME
+.B mftl
+\- find and list usable-looking targets in Makefiles
+.SH SYNOPSIS
+.B
+mftl
+Makefile
+.br
+.B
+mftl
+Makefile1 Makefile2
+.br
+grep -v foo Makefile |
+.B
+mftl
+.SH DESCRIPTION
+.B mftl
+searches for targets in a Makefile specified as either targets or dependencies.
+Any targets it finds that are simple strings or filenames that look like they
+should be referenced by the user, are printed uniquely sorted to stdout.
+.P
+This is not 100% accurate (and probably can't be); GNU Make's heresies make it
+particularly complicated. For simple POSIX-ish Makefiles, it should work well.
+The idea is to get an overview of what's accessible in a Makefile without
+having to page through the whole thing.
+.SH SEE ALSO
+make(1)
+.SH AUTHOR
+Tom Ryder <tom@sanctum.geek.nz>
-- 
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