Different ASTs from codes the same in meaning

[eliben]

Different ASTs from codes the same in meaning

[w-vi]

pycparser is a parser and from parser you don't expect any understanding for semantics. I consider this a correct behaviour as I actually want to know if there are braces or not that is if it is a compound statement or not. You need to handle this on your side as this really depends on what you want to do. These ASTs are different because the code is different and AST represents code not meaning or anything else.

[eliben]

As I noted in a different issue, pycparser makes no attempt to preserve syntactic information. It produces an AST, not a parse tree [http://eli.thegreenplace.net/2009/02/16/abstract-vs-concrete-syntax-trees/]

The example here is just one small one, there's an infinite amount of them - you can not faithfully reproduce the incoming source from pycparser; it's not, has never been, its design goal.

[akiradeveloper]

Thank you for your persuasive comments. I will do on my side.

[akiradeveloper]

I think this visitor braces all unbraced statements.

I referred to BNF grammer here and thought these are complete.
http://www.lysator.liu.se/c/ANSI-C-grammar-y.html#statement

class Brace(c_ast.NodeVisitor):

        def visit_If(self, n):
                if not isinstance(n.iftrue, c_ast.Compound):
                        comp = c_ast.Compound([n.iftrue])
                        n.iftrue = comp
                if not isinstance(n.iffalse, c_ast.Compound):
                        comp = c_ast.Compound([n.iffalse])
                        n.iffalse = comp
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_Case(self, n):
                if not isinstance(n.stmts, c_ast.Compound):
                        comp = c_ast.Compound(n.stmts)
                        n.stmts = [comp]
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_Default(self, n):
                if not isinstance(n.stmts, c_ast.Compound):
                        comp = c_ast.Compound(n.stmts)
                        n.stmts = [comp]
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_Switch(self, n):
                if not isinstance(n.stmt, c_ast.Compound):
                        comp = c_ast.Compound([n.stmt])
                        n.stmt = comp
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_For(self, n):
                if not isinstance(n.stmt, c_ast.Compound):
                        comp = c_ast.Compound([n.stmt])
                        n.stmt = comp
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_While(self, n):
                if not isinstance(n.stmt, c_ast.Compound):
                        comp = c_ast.Compound([n.stmt])
                        n.stmt = comp
                c_ast.NodeVisitor.generic_visit(self, n)

        def visit_DoWhile(self, n):
                if not isinstance(n.stmt, c_ast.Compound):
                        comp = c_ast.Compound([n.stmt])
                        n.stmt = comp
                c_ast.NodeVisitor.generic_visit(self, n)