def parsesingle(s, strictmode=True, expansionlimit=None, convertpos=False):
'''like parse, but only consumes a single top level node, e.g. parsing
'a\nb' will only return a node for 'a', leaving b unparsed'''
p = _parser(s, strictmode=strictmode, expansionlimit=expansionlimit)
tree = p.parse()
if convertpos:
bast.posconverter(s).visit(tree)
return tree
def parse(s, strictmode=True, expansionlimit=None, convertpos=False):
'''parse the input string, returning a list of nodes
top level node kinds are:
- command - a simple command
- pipeline - a series of simple commands
- list - a series of one or more pipelines
- compound - contains constructs for { list; }, (list), if, for..
leafs are word nodes (which in turn can also contain any of the
aforementioned nodes due to command substitutions).
when strictmode is set to False, we will:
- skip reading a heredoc if we're at the end of the input
expansionlimit is used to limit the amount of recursive parsing done due to
command substitutions found during word expansion.
'''
p = _parser(s, strictmode=strictmode, expansionlimit=expansionlimit)
parts = [p.parse()]
class endfinder(bast.nodevisitor):
def __init__(self):
self.end = -1
def visitheredoc(self, node, value):
self.end = node.pos[1]
# find the 'real' end incase we have a heredoc in there
ef = _endfinder()
ef.visit(parts[-1])
index = max(parts[-1].pos[1], ef.end) + 1
while index < len(s):
part = _parser(s[index:], strictmode=strictmode).parse()
if not isinstance(part, bast.node):
break
bast.posshifter(index).visit(part)
parts.append(part)
ef = _endfinder()
ef.visit(parts[-1])
index = max(parts[-1].pos[1], ef.end) + 1
if convertpos:
for tree in parts:
bast.posconverter(s).visit(tree)
return parts