Added a command line script to ~/tools to count...

Added a command line script to ~/tools to count flag usages. I'm
checking this in less out of the enormous demand for flag counting
scripts than because I wanted to lower the barrier to people writing
reusable bash scripts.

  *** DO YOU WANT TO WRITE NICE BASH SCRIPTS? ***

  ***    Look at tools/flag-usages.sh    ***

  *** It's easy to understand and full of helpful comments! ***

I'm not making any claims here about having massive bash expertise,
but I know a lot of people resist learning any of it (I was once like
you) so I wanted to lower the barrier a little. Because as a mechanism
for the composition and modification of the world of existing tools,
nothing comes close to the shell. And I know many of us write way too
many one-offs which we delete in shame and horror shortly after their
immediate purpose is served.

No review. (I should say r-e-v-i-e-w by everyone but I'm sure it would
give me a nice pile of crucible errors.)

1 files changed, 67 insertions, 0 deletions

diff --git a/tools/flag-usages.sh b/tools/flag-usages.sh
new file mode 100755
index 0000000000..82696bd1da
--- /dev/null
+++ b/tools/flag-usages.sh
@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+#
+# find-flag-usages
+# Paul Phillips <paulp@typesafe.com>
+#
+# Looks through the scala source tree for direct references to flag names.
+
+set -e  # Good idea in almost all scripts: causes script to exit on any error.
+
+# Would be better not to hardcode this.
+flags='\b(ABSOVERRIDE|ABSTRACT|ACCESSOR|BRIDGE|BYNAMEPARAM|CAPTURED|CASE|CASEACCESSOR|CONTRAVARIANT|COVARIANT|DEFAULTINIT|DEFAULTPARAM|DEFERRED|EXISTENTIAL|EXPANDEDNAME|FINAL|IMPLCLASS|IMPLICIT|INCONSTRUCTOR|INTERFACE|JAVA|LABEL|LAZY|LIFTED|LOCAL|LOCKED|METHOD|MIXEDIN|MODULE|MODULEVAR|MUTABLE|OVERLOADED|OVERRIDE|PACKAGE|PARAM|PARAMACCESSOR|PRESUPER|PRIVATE|PROTECTED|SEALED|SPECIALIZED|STABLE|STATIC|SUPERACCESSOR|SYNTHETIC|TRAIT|TRIEDCOOKING|VARARGS|VBRIDGE)\b'
+
+# $() runs a command in a subshell.  This is calculating the root of the
+# repository by looking relative to the location of the script.
+rootdir=$(cd $(dirname $0) ; pwd)/..
+
+# A bash function.  Can be used like a command.
+usage () {
+  # A here string.  Allows for blocks of text without lots of quoting.
+  # Variable interpolation still takes place, e.g. $(basename $0).
+  cat <<EOM
+Usage: $(basename $0) [-achs]
+  -a show all flag usages
+  -c count flag usages per file
+  -h show this message
+  -s count total flag usages
+EOM
+}
+
+# Checking for no arguments or missing requirements.
+if [[ $# -eq 0 ]]; then
+  usage
+  exit 1
+elif [[ ! $(which ack) ]]; then   # no ack
+  echo "Error: cannot find required program ack."
+  exit 1
+fi
+
+# Using pushd/popd for directory changes is a way to make moving
+# the current directory around somewhat more composable.
+pushd "$rootdir" >/dev/null
+
+# The leading : in :achs suppresses some errors. Each letter is a valid
+# option. If an option takes an argument, a colon follows it, e.g.
+# it would be :ach:s if -h took an argument.
+while getopts :achs opt; do
+  case $opt in
+    a) ack "$flags" src ;;
+    c) ack --files-with-matches -c "$flags" src ;;
+    h) usage ;;
+    s) ack --no-filename -o "$flags" src | sort | uniq -c | sort -gr ;;
+    :) echo "Option -$OPTARG requires an argument." >&2 ;;      # this case is called for a missing option argument
+    *) echo "Unrecognized argument $OPTARG" ;;                  # this is the catch-all implying an unknown option
+  esac
+done
+
+# This removes all the options from $@, as getopts doesn't touch it.
+# After this, "$@" contains the non-option arguments.
+shift $((OPTIND-1))
+
+# In this program we don't expect any.
+if [[ $# -ne 0 ]]; then
+  echo "This program does not take arguments."
+fi
+
+popd >/dev/null
+exit 0