Format text is literal; class runs are {digits(n)} {upper(n)} {lower(n)}; a string is a format

format-migration/convert.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Rewrite data files from the class-char format grammar to the literal-text one.
+
+    convert.py data/sv_SE/person.json ...
+
+Old: 0 1 A a are character classes, # escapes.  New: text is literal; a run of
+0/A/a becomes {digits(n)}/{upper(n)}/{lower(n)}, 1 followed by n zeros becomes
+{int(10^n, 10^(n+1)-1)}, a literal brace becomes {{ or }}.
+"""
+import re
+import sys
+
+RUN = {"0": "{{digits({})}}", "A": "{{upper({})}}", "a": "{{lower({})}}"}
+
+
+def literal(c):
+	return {"{": "{{", "}": "}}"}.get(c, c)
+
+
+def convert_format(f):
+	out, i, n = [], 0, len(f)
+	while i < n:
+		c = f[i]
+		if c == "#":
+			i += 1
+			if i < n:
+				out.append(literal(f[i]))
+				i += 1
+			else:
+				out.append("#")
+		elif c == "{":
+			j = f.find("}", i)
+			if j < 0:
+				out.append(f[i:])
+				break
+			out.append(f[i:j + 1])
+			i = j + 1
+		elif c in RUN:
+			k = 0
+			while i < n and f[i] == c:
+				k += 1
+				i += 1
+			out.append(RUN[c].format(k))
+		elif c == "1":
+			i += 1
+			k = 0
+			while i < n and f[i] == "0":
+				k += 1
+				i += 1
+			out.append("{{int({},{})}}".format(10 ** k, 10 ** (k + 1) - 1))
+		else:
+			out.append(literal(c))
+			i += 1
+	return "".join(out)
+
+
+FORMAT_VALUE = re.compile(r'("format":\s*")((?:[^"\\]|\\.)*)(")')
+
+
+def convert_text(text):
+	return FORMAT_VALUE.sub(lambda m: m.group(1) + convert_format(m.group(2)) + m.group(3), text)
+
+
+if __name__ == "__main__":
+	for path in sys.argv[1:]:
+		with open(path) as fh:
+			before = fh.read()
+		after = convert_text(before)
+		if after != before:
+			with open(path, "w") as fh:
+				fh.write(after)
+			print("converted", path)