Question

I have an idea for a simple program to make that will help me with operator precedence in languages like C. The most difficult part of this is parenthesizing the expression. For example, I want this:

*a.x++ = *b.x++ 

Converted to this:

((*(((a).(x))++)) = (*(((b).(x))++))) 

Which I did manually in these steps:

           *a.x++ = *b.x++        *(a).(x)++ = *(b).(x)++      *((a).(x))++ = *((b).(x))++    *(((a).(x))++) = *(((b).(x))++)  (*(((a).(x))++)) = (*(((b).(x))++)) ((*(((a).(x))++)) = (*(((b).(x))++))) 

What is the best way to accomplish this? Is there already a solution out there that I could use? I’d prefer to do this in either PHP, C, C++, Python, or Ruby.

(This isn’t the whole idea of my program, it is only the first step.)

Answer 1

Just pick up a parser for your selected language, for instance C parser, parse the expression/source code and print the AST back in the way you want.

test.c:

void main(void){     int c = 2; } 

terminal:

$ python >>> import pycparser >>> test = pycparser.parse_file('test.c') >>> test.show() FileAST:    FuncDef:      Decl: main, [], []       FuncDecl:          ParamList:            Typename: []             TypeDecl: None, []               IdentifierType: ['void']         TypeDecl: main, []           IdentifierType: ['void']     Compound:        Decl: c, [], []         TypeDecl: c, []           IdentifierType: ['int']         Constant: int, 2 >>> for node in test.ext: ...     print node ... <pycparser.c_ast.FuncDef object at 0x7fe1436db750> >>>