clang-format: add version-variable clang-format script

src/c/CMakeLists.txt

@@ -8,6 +8,8 @@ foreach(v
   add_formatter(clang-format-${v} reformat clang-format-${v})
   set_property(GLOBAL PROPERTY "formatter_clang-format-${v}_exclude_from_all" "1")
 endforeach()
+add_formatter(clang-format reformat clang-format)
+set_property(GLOBAL PROPERTY "formatter_clang-format_exclude_from_all" "1")
 add_formatter(clang-format-kwsys reformat clang-format-3.8)
 set_property(GLOBAL PROPERTY "formatter_clang-format-kwsys_exclude_from_all" "1")
 add_formatter(uncrustify reformat uncrustify)

src/c/format.clang-format

+#!/bin/sh
+# This formatter uses the `clang-format` tool to perform
+# formatting of files written in C, C++, and other C-like
+# languages (CUDA, GLSL, etc.).
+#
+# It uses the `clang-format` executable in `$PATH` and checks for
+# the existence of the `.clang-format` file as its configuration.
+
+set -e
+
+readonly path="$1"
+shift
+
+if [ "$#" -ne 0 ]; then
+    readonly version="-$1"
+    shift
+else
+    version=""
+fi
+readonly value
+
+if ! [ -f "$path" ]; then
+    echo >&2 'error: could not find file to format: '"$path"
+    exit 4
+fi
+
+if ! which "clang-format$version" > /dev/null; then
+    echo >&2 'error: could not find the `clang-format'"$version"'` binary'
+    exit 3
+fi
+
+if ! [ -f ".clang-format" ]; then
+    echo >&2 'error: the `.clang-format` file is missing'
+    exit 2
+fi
+
+exec "clang-format$version" -i "$path"

test/clang-format/CMakeLists.txt

+add_formatter_test(clang-format pass format.c pass)
+add_formatter_test(clang-format format format.c format)
+add_formatter_test(clang-format no-config-file format.c fail)

test/clang-format/format/.clang-format

+---
+Language:        Cpp
+...

test/clang-format/format/format.c

+int main(int argc, char *argv[]) {
+    return 0;
+}

test/clang-format/format/format.c.clean

+int main(int argc, char *argv[]) {
+    return 0;
+}

test/clang-format/format/format.c.expect

+int main(int argc, char *argv[]) { return 0; }

test/clang-format/pass/.clang-format

+---
+Language:        Cpp
+...

test/clang-format/pass/format.c

+int main(int argc, char *argv[]) { return 0; }

test/clang-format/pass/format.c.clean

+int main(int argc, char *argv[]) { return 0; }