Propose semver version script for #45

contrib/semver/version.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+# Get the last tag
+TAG=$(git describe --abbrev=0 --tags 2>/dev/null)
+
+# Get the number of commits from the last tag, or if not, from
+# the first commit
+COUNT=$( \
+  git rev-list v$TAG..HEAD --count 2>/dev/null || \
+  git rev-list HEAD --count 2>/dev/null \
+)
+
+# Check if it matches the vX.Y.Z format
+grep "v[0-9]*\.[0-9]*\.[0-9]*" <<< $TAG &>/dev/null
+
+# If it doesn't, abort
+if [ $? -ne 0 ]; then
+  printf 'v0.0.0-%d' "$COUNT"
+  exit -1
+fi
+
+# Trim the "v" off the front
+TAG=$(echo $TAG | cut -c 2-)
+
+# Split out into major, minor and patch numbers
+MAJOR=$(echo $TAG | cut -d "." -f 1)
+MINOR=$(echo $TAG | cut -d "." -f 2)
+PATCH=$(echo $TAG | cut -d "." -f 3)
+
+# Output in the desired format
+printf 'v%d.%d.%d-%d' "$MAJOR" "$MINOR" "$PATCH" "$COUNT"