~/bin/diffnore

#!/bin/sh
usage() {
    exec >&2
    echo "Usage: $0 [-d|-v] [-R regex] [-A regex]"
    echo "Options:"
    local optfmt="\t%-10s %s\n"
    printf "$optfmt" "-d" "Debug. Output all lines without processing."
    printf "$optfmt" "-v" "Verbose. Show ignore status for each hunk."
    printf "$optfmt" "-A regex" "Ignore additions matching regex."
    printf "$optfmt" "-R regex" "Ignore removals matching regex."
    exit 1
}
addignore=
rmignore=
verbose=0
while getopts A:dR:v flag; do
    case "$flag" in
    A) addignore="$OPTARG" ;;
    d) debug=1 ;;
    R) rmignore="$OPTARG" ;;
    v) verbose=1 ;;
    *) usage
    esac
done
shift $(( $OPTIND - 1 ))
svn diff -x -p | awk \
    -v addignore="$addignore" \
    -v debug="$debug" \
    -v rmignore="$rmignore" \
    -v verbose="$verbose" ' # START-AWK
debug { print; next }
/^--- / { file++; getline; files[file] = $2; hunk = 0; next }
/^@@ / { hunks[file] = ++hunk; rm = add = 0; next }
/^-/ { if (!rmignore || $0 !~ rmignore) rms[file,hunk] = ++rm }
/^\+/ { if (!addignore || $0 !~ addignore) adds[file,hunk] = ++add }
END { for (f = 1; f <= file; f++) {
    if (verbose) printf "%4s > %s (%u hunks)\n", "#" f, files[f], hunks[f]
    for (h = 1; h <= hunks[f]; h++) {
        if (verbose) printf "%6s Hunk %3u = -%u/+%u",
            "", h, rms[f,h], adds[f,h]
        ignore = (rms[f,h] < 1 && adds[f,h] < 1)
        if (verbose) printf " %s\n", ignore ? "**IGNORED**" : ""
        else if (ignore) print "ignore", files[f]
    }
}}' # END-AWK