#------------------------------------------------------------------------------
# pycparser: cython_generator.py
#
# Cython code generator from pycparser AST nodes.
#
# Copyright (C) 2008-2012, Eli Bendersky and Brett Hartshorn
# License: BSD
#------------------------------------------------------------------------------
from . import c_ast
CLASSIFY = True
MARKER = '#######$$$$$'
class CythonGenerator(object):
""" Uses the same visitor pattern as c_ast.NodeVisitor, but modified to
return a value from each visit method, using string accumulation in
generic_visit.
"""
def __init__(self):
self.output = ''
# Statements start with indentation of self.indent_level spaces, using
# the _make_indent method
#
self.indent_level = 0
self.classes = {} # dict of class (typedef) names of generated classes : []
def visit_FileAST(self, n):
s = ''
for ext in n.ext:
if isinstance(ext, c_ast.FuncDef):
s += self.visit(ext)
else:
s += self.visit(ext) + ';\n'
for class_name in self.classes:
funcs = self.classes[ class_name ]
a = []
for func in funcs:
for i,line in enumerate(func.splitlines()):
a.append( ' '+line )
s = s.replace(MARKER+class_name, '\n'.join(a))
result = [] ## clean up
for line in s.splitlines():
if line.endswith(';'): line = line[:-1]
if line.strip(): result.append( line )
return '\n'.join( result )
def _make_indent(self):
return ' ' * self.indent_level
def visit(self, node, cdef=True):
method = 'visit_' + node.__class__.__name__
print(method)
if method in 'visit_Decl visit_ParamList'.split():
return getattr(self, method, self.generic_visit)(node, cdef=cdef)
else:
return getattr(self, method, self.generic_visit)(node)
def generic_visit(self, node):
#~ print('generic:', type(node))
if node is None:
return ''
else:
return ''.join(self.visit(c) for c in node.children())
def visit_Constant(self, n):
return n.value
def visit_ID(self, n):
return n.name
def visit_ArrayRef(self, n):
arrref = self._parenthesize_unless_simple(n.name)
return arrref + '[' + self.visit(n.subscript) + ']'
def visit_StructRef(self, n):
sref = self._parenthesize_unless_simple(n.name)
if CLASSIFY: n.type = '.' # TODO check if struct is in self.classes or 'self'
return sref + n.type + self.visit(n.field)
def visit_FuncCall(self, n):
fref = self._parenthesize_unless_simple(n.name)
if fref == 'printf': fref = 'print'
return fref + '(' + self.visit(n.args) + ')'
def visit_UnaryOp(self, n):
operand = self._parenthesize_unless_simple(n.expr)
if n.op == 'p++':
return '%s += 1' % operand
elif n.op == 'p--':
return '%s -= 1' % operand
elif n.op == 'sizeof':
# Always parenthesize the argument of sizeof since it can be
# a name.
return 'sizeof(%s)' % self.visit(n.expr)
else:
return '%s%s' % (n.op, operand)
def visit_BinaryOp(self, n):
lval_str = self._parenthesize_if(n.left,
lambda d: not self._is_simple_node(d))
rval_str = self._parenthesize_if(n.right,
lambda d: not self._is_simple_node(d))
return '%s %s %s' % (lval_str, n.op, rval_str)
def visit_Assignment(self, n):
rval_str = self._parenthesize_if(
n.rvalue,
lambda n: isinstance(n, c_ast.Assignment))
return '%s %s %s' % (self.visit(n.lvalue), n.op, rval_str)
def visit_IdentifierType(self, n):
return ' '.join(n.names)
def visit_Decl(self, n, no_type=False, cdef=True):
# no_type is used when a Decl is part of a DeclList, where the type is
# explicitly only for the first delaration in a list.
#
s = n.name if no_type else self._generate_decl(n)
print('visit_Decl', s)
n.show()
print( n.type, type(n.type) )
if not isinstance(n.type, (c_ast.Enum, c_ast.Struct)):
s = 'cdef ' + s
if n.bitsize: s += ' : ' + self.visit(n.bitsize)
if n.init:
if isinstance(n.init, c_ast.InitList):
s += ' = {' + self.visit(n.init) + '}'
elif isinstance(n.init, c_ast.ExprList):
s += ' = (' + self.visit(n.init) + ')'
else:
s += ' = ' + self.visit(n.init)
return s
def visit_DeclList(self, n):
s = self.visit(n.decls[0])
if len(n.decls) > 1:
s += ', ' + ', '.join(self.visit_Decl(decl, no_type=True)
for decl in n.decls[1:])
return s
def visit_Typedef(self, n):
a = self._generate_type(n.type)
a = '\n'.join( a.splitlines()[:-1] ) # remove name at end.
a = a.replace(';', '')
if n.storage:
s = ' '.join(n.storage) + ' '
s = s.replace('typedef ', 'ctypedef ')
simple = True
sname = None
tname = None
classify = False
if isinstance(n.type, c_ast.TypeDecl):
if isinstance(n.type.type, c_ast.Struct):
sname = n.type.type.name
tname = n.type.declname
if CLASSIFY:
classify = True
if not n.type.type.name:
simple = True
elif n.type.declname == n.type.type.name:
simple = True
elif n.type.declname != n.type.type.name:
simple = False
if classify:
return self.struct_to_class(a, sname, tname)
elif simple:
if a.startswith('cdef '):
a = a[5:]
return s + a
else:
return a + '\nctypedef %s %s\n'%(n.type.type.name, n.type.declname)
else:
return a
def struct_to_class(self, txt, struct_name, type_name):
head = txt.splitlines()[0]
body = txt.splitlines()[1:]
head = head.replace(' struct ', ' class ')
if not struct_name:
head = head.replace(':', '%s:'%type_name)
elif type_name != struct_name:
head = head.replace('%s:'%struct_name, '%s:'%type_name)
lines = [ head ]
args = ['self'] # no need to type self
init = []
for line in body:
a = line.strip()
lines.append( ' cdef public %s'%a)
args.append( a )
n = a.split()[-1]
init.append( ' self.%s = %s'%(n,n) )
## __init__ requires "def" not "cdef"
lines.append( ' def __init__(%s):'%(','.join(args)) )
lines.extend( init )
lines.append(MARKER+type_name)
assert type_name not in self.classes
self.classes[ type_name ] = [] # list of methods
return '\n'.join( lines )
def visit_Cast(self, n):
s = '(' + self._generate_type(n.to_type) + ')'
return s + ' ' + self._parenthesize_unless_simple(n.expr)
def visit_ExprList(self, n):
visited_subexprs = []
for expr in n.exprs:
if isinstance(expr, c_ast.ExprList):
visited_subexprs.append('{' + self.visit(expr) + '}')
else:
visited_subexprs.append(self.visit(expr))
return ', '.join(visited_subexprs)
def visit_InitList(self, n):
visited_subexprs = []
for expr in n.exprs:
if isinstance(expr, c_ast.InitList):
visited_subexprs.append('(' + self.visit(expr) + ')')
else:
visited_subexprs.append(self.visit(expr))
return ', '.join(visited_subexprs)
def visit_Enum(self, n):
s = '# enum'
if n.name: s += ' ' + n.name
items = []
if n.values:
for i, enumerator in enumerate(n.values.enumerators):
if enumerator.value:
items.append( 'cdef int '+enumerator.name + ' = ' + self.visit(enumerator.value) )
else:
items.append( 'cdef int '+enumerator.name + ' = %s'%i)
return s + '\n' + '\n'.join( items )
def visit_FuncDef(self, n):
print('visit funcdef', n.decl)
classify = False
funcdecl = n.decl.type
if CLASSIFY and funcdecl.args:
arg = funcdecl.args.params[0]
if isinstance(arg, c_ast.Decl) and isinstance(arg.type, c_ast.PtrDecl):
ptr = arg.type
if isinstance( ptr.type, c_ast.TypeDecl) and isinstance(ptr.type.type, c_ast.IdentifierType):
name = ptr.type.type.names[0]
if name in self.classes:
self.function_to_method( n, name, arg.name )
classify = (name, arg.name)
decl = self.visit(n.decl) + ':'
decl = 'cpdef ' + decl.replace('cdef ', '') ## to keep things simple just remove "cdef " from parameters
self.indent_level = 0
body = self.visit(n.body)
if n.param_decls:
knrdecls = ';\n'.join(self.visit(p) for p in n.param_decls)
result = decl + '\n' + knrdecls + ';\n' + body + '\n'
else:
result = decl + '\n' + body + '\n'
if classify:
cname, vname = classify
result = result.replace('*'+vname, '')
self.classes[ cname ].append( result )
return ''
else:
return result
def function_to_method(self, n, class_name, var_name):
print( 'n', n, class_name, var_name)
for a in n.children():
tag, child = a
print('child', child)
if isinstance(child, c_ast.IdentifierType):
if len(child.names)==1 and child.names[0] == class_name:
child.names[0] = 'self'
elif isinstance(child, c_ast.ID) and child.name == var_name:
child.name = 'self'
else:
self.function_to_method( child, class_name, var_name )
def visit_Compound(self, n):
#s = self._make_indent() + '{\n'
s = self._make_indent() + '\n'
self.indent_level += 2
if n.block_items:
s += ''.join(self._generate_stmt(stmt) for stmt in n.block_items)
self.indent_level -= 2
#s += self._make_indent() + '}\n'
s += self._make_indent() + '\n'
return s
def visit_EmptyStatement(self, n):
return ';'
def visit_ParamList(self, n, cdef=False):
return ', '.join(self.visit(param, cdef=cdef) for param in n.params)
def visit_Return(self, n):
s = 'return'
if n.expr: s += ' ' + self.visit(n.expr)
return s + ';'
def visit_Break(self, n):
return 'break;'
def visit_Continue(self, n):
return 'continue;'
def visit_TernaryOp(self, n):
s = self.visit(n.cond) + ' ? '
s += self.visit(n.iftrue) + ' : '
s += self.visit(n.iffalse)
return s
def visit_If(self, n):
s = 'if ('
if n.cond: s += self.visit(n.cond)
s += '):\n'
s += self._generate_stmt(n.iftrue, add_indent=True)
if n.iffalse:
s += self._make_indent() + 'else:\n'
s += self._generate_stmt(n.iffalse, add_indent=True)
return s
def is_simple_for_loop(self, n):
if isinstance(n.init, c_ast.Assignment) and n.init.op=='=' and isinstance(n.init.lvalue, c_ast.ID):
if isinstance( n.init.rvalue, c_ast.Constant) and isinstance( n.cond, c_ast.BinaryOp):
if isinstance( n.next, c_ast.UnaryOp ) and n.next.op == 'p++':
return True
return False
def visit_For(self, n):
if self.is_simple_for_loop( n ):
var = n.init.lvalue.name
start = n.init.rvalue.value
s = 'for %s from %s <= %s'%(var,start,var)
s += ' %s %s:\n'%(n.cond.op, n.cond.right.name)
else: ## not cython yet TODO
s = 'for ('
if n.init: s += self.visit(n.init)
s += ';'
if n.cond: s += ' ' + self.visit(n.cond)
s += ';'
if n.next: s += ' ' + self.visit(n.next)
s += '):\n'
s += self._generate_stmt(n.stmt, add_indent=True)
return s
def visit_While(self, n):
s = 'while ('
if n.cond: s += self.visit(n.cond)
s += '):\n'
s += self._generate_stmt(n.stmt, add_indent=True)
return s
def visit_DoWhile(self, n):
s = 'do\n'
s += self._generate_stmt(n.stmt, add_indent=True)
s += self._make_indent() + 'while ('
if n.cond: s += self.visit(n.cond)
s += ');'
return s
def visit_Switch(self, n):
s = 'switch (' + self.visit(n.cond) + ')\n'
s += self._generate_stmt(n.stmt, add_indent=True)
return s
def visit_Case(self, n):
s = 'case ' + self.visit(n.expr) + ':\n'
for stmt in n.stmts:
s += self._generate_stmt(stmt, add_indent=True)
return s
def visit_Default(self, n):
s = 'default:\n'
for stmt in n.stmts:
s += self._generate_stmt(stmt, add_indent=True)
return s
def visit_Label(self, n):
return n.name + ':\n' + self._generate_stmt(n.stmt)
def visit_Goto(self, n):
return 'goto ' + n.name + ';'
def visit_EllipsisParam(self, n):
return '...'
def visit_Struct(self, n):
return self._generate_struct_union(n, 'struct')
def visit_Typename(self, n):
return self._generate_type(n.type)
def visit_Union(self, n):
return self._generate_struct_union(n, 'union')
def visit_NamedInitializer(self, n):
s = ''
for name in n.name:
if isinstance(name, c_ast.ID):
s += '.' + name.name
elif isinstance(name, c_ast.Constant):
s += '[' + name.value + ']'
s += ' = ' + self.visit(n.expr)
return s
def _generate_struct_union(self, n, name):
""" Generates code for structs and unions. name should be either
'struct' or union.
"""
a = 'cdef ' + name + ' ' + (n.name or '') + ':'
if n.decls:
s = '\n'
s += self._make_indent()
self.indent_level += 2
for decl in n.decls:
s += self._generate_stmt(decl)
self.indent_level -= 2
s += self._make_indent()
return a + s.replace('cdef ', '')
def _generate_struct_union_as_class(self, n, name):
""" Generates code for structs and unions. name should be either
'struct' or union.
"""
assert n.name ## TODO unnamed structs
s = 'cdef class %s:'%n.name
if n.decls:
s += '\n'
s += self._make_indent()
self.indent_level += 2
for decl in n.decls:
s += self._generate_stmt(decl)
self.indent_level -= 2
s += self._make_indent()
return s
def _generate_stmt(self, n, add_indent=False):
""" Generation from a statement node. This method exists as a wrapper
for individual visit_* methods to handle different treatment of
some statements in this context.
"""
typ = type(n)
if add_indent: self.indent_level += 2
indent = self._make_indent()
if add_indent: self.indent_level -= 2
if typ in (
c_ast.Decl, c_ast.Assignment, c_ast.Cast, c_ast.UnaryOp,
c_ast.BinaryOp, c_ast.TernaryOp, c_ast.FuncCall, c_ast.ArrayRef,
c_ast.StructRef, c_ast.Constant, c_ast.ID, c_ast.Typedef):
# These can also appear in an expression context so no semicolon
# is added to them automatically
#
return indent + self.visit(n) + ';\n'
elif typ in (c_ast.Compound,):
# No extra indentation required before the opening brace of a
# compound - because it consists of multiple lines it has to
# compute its own indentation.
#
return self.visit(n)
else:
return indent + self.visit(n) + '\n'
def _generate_decl(self, n):
""" Generation from a Decl node.
"""
s = ''
if n.funcspec: s = ' '.join(n.funcspec) + ' '
if n.storage: s += ' '.join(n.storage) + ' '
s += self._generate_type(n.type)
return s
def _generate_type(self, n, modifiers=[]):
""" Recursive generation from a type node. n is the type node.
modifiers collects the PtrDecl, ArrayDecl and FuncDecl modifiers
encountered on the way down to a TypeDecl, to allow proper
generation from it.
"""
typ = type(n)
#~ print(n, modifiers)
if typ == c_ast.TypeDecl:
s = ''
if n.quals: s += ' '.join(n.quals) + ' '
s += self.visit(n.type)
nstr = n.declname if n.declname else ''
# Resolve modifiers.
# Wrap in parens to distinguish pointer to array and pointer to
# function syntax.
#
for i, modifier in enumerate(modifiers):
if isinstance(modifier, c_ast.ArrayDecl):
if (i != 0 and isinstance(modifiers[i - 1], c_ast.PtrDecl)):
nstr = '(' + nstr + ')'
nstr += '[' + self.visit(modifier.dim) + ']'
elif isinstance(modifier, c_ast.FuncDecl):
if (i != 0 and isinstance(modifiers[i - 1], c_ast.PtrDecl)):
nstr = '(' + nstr + ')'
nstr += '(' + self.visit(modifier.args) + ')'
elif isinstance(modifier, c_ast.PtrDecl):
if modifier.quals:
nstr = '* %s %s' % (' '.join(modifier.quals), nstr)
else:
nstr = '*' + nstr
if nstr: s += ' ' + nstr
return s
elif typ == c_ast.Decl:
return self._generate_decl(n.type)
elif typ == c_ast.Typename:
return self._generate_type(n.type)
elif typ == c_ast.IdentifierType:
return ' '.join(n.names) + ' '
elif typ in (c_ast.ArrayDecl, c_ast.PtrDecl, c_ast.FuncDecl):
return self._generate_type(n.type, modifiers + [n])
else:
return self.visit(n)
def _parenthesize_if(self, n, condition):
""" Visits 'n' and returns its string representation, parenthesized
if the condition function applied to the node returns True.
"""
s = self.visit(n)
if condition(n):
return '(' + s + ')'
else:
return s
def _parenthesize_unless_simple(self, n):
""" Common use case for _parenthesize_if
"""
return self._parenthesize_if(n, lambda d: not self._is_simple_node(d))
def _is_simple_node(self, n):
""" Returns True for nodes that are "simple" - i.e. nodes that always
have higher precedence than operators.
"""
return isinstance(n,( c_ast.Constant, c_ast.ID, c_ast.ArrayRef,
c_ast.StructRef, c_ast.FuncCall))