import os
import glob
+class SubstitutionError(Exception):
+ pass
+
def search(c):
DEFAULT = 0
DOLLAR = 1
state = DEFAULT
i += 1
if depth != 0:
- raise Exception("Substitution error, mismatched parentheses {}".format(c))
+ raise SubstitutionError("Substitution error, mismatched parentheses {}".format(c))
return None
def sub_file(v):
def sub_glob(v):
l = glob.glob(v)
if len(l) == 0:
- raise Exception("$(glob): No match on '%s'" % v)
+ raise SubstitutionError("$(glob): No match on '%s'" % v)
else:
return l[0]
def do_substitution(p, c, subs=default_subs):
while True:
- #print("c is", c)
m = search(c)
- if m is not None:
- v = do_substitution(p, c[m[0]+2 : m[1]])
- var = True
- for sub in subs:
- if v.startswith(sub):
- r = subs[sub](v[len(sub):])
- var = False
- break
- if var:
+ if m is None:
+ return c
+
+ v = do_substitution(p, c[m[0]+2 : m[1]])
+ var = True
+ for sub in subs:
+ if v.startswith(sub):
+ r = subs[sub](v[len(sub):])
+ var = False
+ break
+ if var:
+ if v in p:
r = p[v]
+ else:
+ raise SubstitutionError("Unknown variable or function '%s' while performing substitution on '%s'" % (v, c))
+ if r is None:
+ raise SubstitutionError("Substitution for '%s' is null while performing substitution on '%s'" % (v, c))
+ if not isinstance(r, basestring):
+ raise SubstitutionError("Substitution for '%s' must be a string while performing substitution on '%s'" % (v, c))
- c = c[:m[0]] + r + c[m[1]+1:]
- else:
- return c
+ c = c[:m[0]] + r + c[m[1]+1:]