initial commit

3 files changed, 108 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..86aab59
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,6 @@
+# test:
+#	
+
+test.json:
+	curl https://httpbin.org/json > test.json
+
diff --git a/mp b/mp
new file mode 100755
index 0000000..337f316
--- /dev/null
+++ b/mp
@@ -0,0 +1,99 @@
+#!/usr/bin/awk -f
+
+BEGIN {
+	version = "2025-07-08"
+
+	help[""] = "Commands:\n" \
+		"  help [cmd]   prints cmd help or this help text\n"
+
+	help["help"] = "help [cmd]\n" \
+		"  Prints cmd help or general help text.\n" \
+		"  Example: help help\n"
+
+	filename = ARGV[1]
+	ARGV[1] = "/dev/stdin"
+	tty = 1 - system("test -t 0")
+	if (filename) src = getfile(filename)
+	prompt("mp-" version " meta parser. Type \"help\" for help.\n")
+}
+$1 == "help" {
+	prompt(help[$2])
+	next
+}
+$1 == "src" {
+	prompt(src)
+	next
+}
+$1 == "parse" {
+	delete v
+	if ($2) parse_json($2, v); else parse_json(src, v)
+	for (k in v) print "v[" k "]: " v[k]
+	prompt()
+	next
+}
+{
+	if (NF) error("invalid command: " $1)
+	prompt()
+}
+
+function error(s) { ERROR = s }
+
+function prompt(s) {
+	if (ERROR) {
+		print ERROR > "/dev/stderr"
+		ERROR = ""
+	}
+	if (tty) printf("%smp> ", s)
+}
+
+function getfile(name,  l, r, o) {
+	while (r = getline l < name) {
+		if (r == -1) {
+			error = "getfile " name ": getline error"
+			break
+		}
+		o = o l "\n"
+	}
+	close(name)
+	return o
+}
+
+# parse the next json value in s, returns the number of characters read.
+function parse_json(s, a, p,    c, i, n) {
+	if (match(s, /^[[:space:]]+/)) {
+		n = RLENGTH
+		s = substr(s, RLENGTH+1)
+	}
+	if (!s) return n
+	if (match(s, /^null|true|false/)) {
+		a[p, "type"] = substr(s, 1, RLENGTH)
+		return n + RLENGTH
+	}
+	if (match(s, /^[.0-9Ee+-]+/)) {
+		a[p, "type"] = "number"
+		a[p, "string"] = substr(s, 1, RLENGTH)
+		return n + RLENGTH
+	}
+	if (match(s, /^"(\\.|[^\\"])*"/)) {
+		a[p, "type"] = "string"
+		a[p, "string"] = substr(s, 2, RLENGTH-2)
+		return n + RLENGTH
+	}
+	c = substr(s, 1, 1)
+	if (c == "{") {
+		a[p, "type"] = "object"
+		i = 0
+		n++
+		s = substr(s, 2)
+		if (match(s, /^[[:space:]]+/)) {
+			n += RLENGTH
+			s = substr(s, RLENGTH+1)
+		}
+		if (match(s, /^"(\\.|[^\\"])*"/)) {
+			a[p, "key", i] = substr(s, 2, RLENGTH-2)
+		} else {
+			error("invalid key: " s)
+			return n
+		}
+	}
+}
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..83650cf
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,3 @@
+# mp
+
+parsing and repl in awk.