Add ax(1)

3 files changed, 60 insertions, 0 deletions

diff --git a/README.markdown b/README.markdown
index 1beb4e0a..3c1c4acb 100644
--- a/README.markdown
+++ b/README.markdown
@@ -300,6 +300,8 @@ Installed by the `install-bin` target:
     *   `rfct(1)` formats ASCII RFCs
     *   `rfcr(1)` does both, displaying in a pager if appropriate, like a
         `man(1)` reader for RFCs
+*   `ax(1)` evaluates an awk expression given on the command line; intended as
+    a quick way to test how Awk would interpret a given expression.
 *   `dub(1)` lists the biggest entries in a directory.
 *   `edda(1)` provides a means to run `ed(1)` over a set of files preserving
     any options, mostly useful for scripts.
diff --git a/bin/ax b/bin/ax
new file mode 100755
index 00000000..3840acf5
--- /dev/null
+++ b/bin/ax
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+# ax(1): Evaluate an Awk expression given on the command line with an optional
+# format.
+
+# Usage function
+usage() {
+    printf 'ax: USAGE: ax [format] expression\n'
+}
+
+# Check number of arguments
+case $# in
+
+    # If one argument, we assume format is %s
+    1) form=%s expr=$1 ;;
+
+    # If two arguments, first is format, second expression
+    2) form=$1 expr=$2 ;;
+
+    # Any other number of arguments is wrong
+    *)
+        usage >&2
+        exit 2
+        ;;
+esac
+
+# Give help if requested
+case $1 in
+    -h|--help|-\?)
+        usage
+        exit 0
+        ;;
+esac
+
+# Form program
+prog=$(printf '
+    BEGIN {
+        printf "%s\\n", %s
+    }
+' "$form" "$expr")
+
+# Run the program
+awk "$prog"
diff --git a/man/man1/ax.1 b/man/man1/ax.1
new file mode 100644
index 00000000..2e8d7179
--- /dev/null
+++ b/man/man1/ax.1
@@ -0,0 +1,15 @@
+.TH AX 1 "July 2016" "Manual page for ax"
+.SH NAME
+.B ax
+\- evaluate an awk expression
+.SH SYNOPSIS
+.B ax '2.0+3.0'
+.br
+.B ax %.2f 'sin(2)'
+.SH DESCRIPTION
+.B ax
+evaluates an expression given on the command line with awk(1) and prints its
+result using awk's printf, with an optional format specified preceding the
+expression.
+.SH AUTHOR
+Tom Ryder <tom@sanctum.geek.nz>