2023-02-15 19:09:38 +00:00

101 lines
2.3 KiB
Python

# Copyright 2019-present, GraphQL Foundation
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
from casing import snake
from license import C_LICENSE_COMMENT
def struct_name(type):
return 'GraphQLAst' + type
def return_type(type):
if type == 'OperationKind' or type == 'string':
return 'const char *'
if type == 'boolean':
return 'int'
return 'const struct %s *' % struct_name(type)
def field_prototype(owning_type, type, name, nullable, plural):
st_name = struct_name(owning_type)
if plural:
return 'int %s_get_%s_size(const struct %s *node)' % (
st_name, snake(name), st_name)
else:
ret_type = return_type(type)
return '%s %s_get_%s(const struct %s *node)' % (
ret_type, st_name, snake(name), st_name)
class Printer(object):
'''Printer for the pure C interface to the AST.
Merely a set of wrappers around the C++ interface; makes it possible
to use the AST from C code and simplifies the task of writing
bindings for other langugages.
The mapping is as follows:
- For each concrete type, you get an opaque C struct type,
accessible only by pointer.
- For each singular field of a concrete type, you get an accessor
function, returning said field in the obvious way.
- For each plural field of a concrete type, you get an accessor
function telling you its size. For access to elements of a plural
field, you can use the visitor API.
- For each union type, you get nothing specific (REVIEW), but you
can use the visitor API to work around this entirely.
'''
def __init__(self):
self._current_type = None
def start_file(self):
print C_LICENSE_COMMENT + '''/** @generated */
#pragma once
#ifdef __cplusplus
extern "C" {
#endif
'''
def end_file(self):
print '''
#ifdef __cplusplus
}
#endif
'''
def start_type(self, name):
# Forward declarations for AST nodes.
st_name = struct_name(name)
print 'struct ' + st_name + ';'
self._current_type = name
def field(self, type, name, nullable, plural):
print field_prototype(self._current_type, type, name, nullable, plural) + ';'
def end_type(self, name):
print
def start_union(self, name):
print 'struct ' + struct_name(name) + ';'
def union_option(self, option):
pass
def end_union(self, name):
print