add hg and python

1 files changed, 56 insertions, 0 deletions

diff --git a/sys/src/cmd/python/Tools/modulator/varsubst.py b/sys/src/cmd/python/Tools/modulator/varsubst.py
new file mode 100644
index 000000000..3b3395065
--- /dev/null
+++ b/sys/src/cmd/python/Tools/modulator/varsubst.py
@@ -0,0 +1,56 @@
+#
+# Variable substitution. Variables are $delimited$
+#
+import re
+
+error = 'varsubst.error'
+
+class Varsubst:
+    def __init__(self, dict):
+        self.dict = dict
+        self.prog = re.compile('\$([a-zA-Z0-9_]*)\$')
+        self.do_useindent = 0
+
+    def useindent(self, onoff):
+        self.do_useindent = onoff
+
+    def subst(self, s):
+        rv = ''
+        while 1:
+            m = self.prog.search(s)
+            if not m:
+                return rv + s
+            rv = rv + s[:m.start()]
+            s = s[m.end():]
+            if m.end() - m.start() == 2:
+                # Escaped dollar
+                rv = rv + '$'
+                s = s[2:]
+                continue
+            name = m.group(1)
+            if not self.dict.has_key(name):
+                raise error, 'No such variable: '+name
+            value = self.dict[name]
+            if self.do_useindent and '\n' in value:
+                value = self._modindent(value, rv)
+            rv = rv + value
+
+    def _modindent(self, value, old):
+        lastnl = old.rfind('\n', 0) + 1
+        lastnl = len(old) - lastnl
+        sub = '\n' + (' '*lastnl)
+        return re.sub('\n', sub, value)
+
+def _test():
+    import sys
+    import os
+
+    sys.stderr.write('-- Copying stdin to stdout with environment map --\n')
+    c = Varsubst(os.environ)
+    c.useindent(1)
+    d = sys.stdin.read()
+    sys.stdout.write(c.subst(d))
+    sys.exit(1)
+
+if __name__ == '__main__':
+    _test()