1e7e9171eSGeorge Keishing#!/usr/bin/env python3 2264bc147SMichael Walsh 3264bc147SMichael Walshr""" 4410b1787SMichael WalshThis module provides functions which are useful for writing python wrapper functions (i.e. in this context, a 5410b1787SMichael Walshwrapper function is one whose aim is to call some other function on the caller's behalf but to provide some 6410b1787SMichael Walshadditional functionality over and above what the base function provides). 7264bc147SMichael Walsh""" 8264bc147SMichael Walsh 9264bc147SMichael Walsh 10*20f38712SPatrick Williamsdef create_func_def_string( 11*20f38712SPatrick Williams base_func_name, wrap_func_name, func_body_template, replace_dict 12*20f38712SPatrick Williams): 13264bc147SMichael Walsh r""" 14410b1787SMichael Walsh Create and return a complete function definition as a string. The caller may run "exec" on the resulting 15410b1787SMichael Walsh string to create the desired function. 16264bc147SMichael Walsh 17264bc147SMichael Walsh Description of argument(s): 18410b1787SMichael Walsh base_func_name The name of the base function around which a wrapper is being created. 19410b1787SMichael Walsh wrap_func_name The name of the wrapper function being created. 20410b1787SMichael Walsh func_body_template A function body in the form of a list. Each list element represents one 21410b1787SMichael Walsh line of a function This is a template in so far as text substitutions 22410b1787SMichael Walsh will be done on it to arrive at a valid function definition. This 23410b1787SMichael Walsh template should NOT contain the function definition line (e.g. "def 24410b1787SMichael Walsh func1():"). create_func_def_string will pre-pend the definition line. 25410b1787SMichael Walsh The template should also contain the text "<call_line>" which is to be 26410b1787SMichael Walsh replaced by text which will call the base function with appropriate 27410b1787SMichael Walsh arguments. 28410b1787SMichael Walsh replace_dict A dictionary indicating additional text replacements to be done. For 29410b1787SMichael Walsh example, if the template contains a "<sub1>" (be sure to include the 30410b1787SMichael Walsh angle brackets), and the dictionary contains a key/value pair of 31410b1787SMichael Walsh 'sub1'/'replace1', then all instances of "<sub1>" will be replaced by 32410b1787SMichael Walsh "replace1". 33264bc147SMichael Walsh """ 34264bc147SMichael Walsh 35264bc147SMichael Walsh # Create the initial function definition list as a copy of the template. 36264bc147SMichael Walsh func_def = list(func_body_template) 370f8b603cSMichael Walsh func_def_line = "def " + wrap_func_name + "(*args, **kwargs):" 380f8b603cSMichael Walsh call_line = base_func_name + "(*args, **kwargs)" 39410b1787SMichael Walsh # Insert the func_def_line composed by create_wrapper_def_and_call is the first list entry. 40264bc147SMichael Walsh func_def.insert(0, func_def_line) 41410b1787SMichael Walsh # Make sure the replace_dict has a 'call_line'/call_line pair so that any '<call_line>' text gets 42410b1787SMichael Walsh # replaced as intended. 43*20f38712SPatrick Williams replace_dict["call_line"] = call_line 44264bc147SMichael Walsh 45264bc147SMichael Walsh # Do the replacements. 46264bc147SMichael Walsh for key, value in replace_dict.items(): 47264bc147SMichael Walsh func_def = [w.replace("<" + key + ">", value) for w in func_def] 48264bc147SMichael Walsh 49*20f38712SPatrick Williams return "\n".join(func_def) + "\n" 50