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Diffstat (limited to 'grc/src/platforms/python/utils/expr_utils.py')
| -rw-r--r-- | grc/src/platforms/python/utils/expr_utils.py | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/grc/src/platforms/python/utils/expr_utils.py b/grc/src/platforms/python/utils/expr_utils.py deleted file mode 100644 index 40700993d..000000000 --- a/grc/src/platforms/python/utils/expr_utils.py +++ /dev/null @@ -1,137 +0,0 @@ -""" -Copyright 2008 Free Software Foundation, Inc. -This file is part of GNU Radio - -GNU Radio Companion is free software; you can redistribute it and/or -modify it under the terms of the GNU General Public License -as published by the Free Software Foundation; either version 2 -of the License, or (at your option) any later version. - -GNU Radio Companion is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with this program; if not, write to the Free Software -Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA -""" - -import string -VAR_CHARS = string.letters + string.digits + '_' - -class graph(object): - """ - Simple graph structure held in a dictionary. - """ - - def __init__(self): self._graph = dict() - - def __str__(self): return str(self._graph) - - def add_node(self, node_key): - if self._graph.has_key(node_key): return - self._graph[node_key] = set() - - def remove_node(self, node_key): - if not self._graph.has_key(node_key): return - for edges in self._graph.values(): - if node_key in edges: edges.remove(node_key) - self._graph.pop(node_key) - - def add_edge(self, src_node_key, dest_node_key): - self._graph[src_node_key].add(dest_node_key) - - def remove_edge(self, src_node_key, dest_node_key): - self._graph[src_node_key].remove(dest_node_key) - - def get_nodes(self): return self._graph.keys() - - def get_edges(self, node_key): return self._graph[node_key] - -def expr_split(expr): - """ - Split up an expression by non alphanumeric characters, including underscore. - Leave strings in-tact. - #TODO ignore escaped quotes, use raw strings. - @param expr an expression string - @return a list of string tokens that form expr - """ - toks = list() - tok = '' - quote = '' - for char in expr: - if quote or char in VAR_CHARS: - if char == quote: quote = '' - tok += char - elif char in ("'", '"'): - toks.append(tok) - tok = char - quote = char - else: - toks.append(tok) - toks.append(char) - tok = '' - toks.append(tok) - return filter(lambda t: t, toks) - -def expr_prepend(expr, vars, prepend): - """ - Search for vars in the expression and add the prepend. - @param expr an expression string - @param vars a list of variable names - @param prepend the prepend string - @return a new expression with the prepend - """ - expr_splits = expr_split(expr) - for i, es in enumerate(expr_splits): - if es in vars: expr_splits[i] = prepend + es - return ''.join(expr_splits) - -def get_variable_dependencies(expr, vars): - """ - Return a set of variables used in this expression. - @param expr an expression string - @param vars a list of variable names - @return a subset of vars used in the expression - """ - expr_toks = expr_split(expr) - return set(filter(lambda v: v in expr_toks, vars)) - -def get_graph(exprs): - """ - Get a graph representing the variable dependencies - @param exprs a mapping of variable name to expression - @return a graph of variable deps - """ - vars = exprs.keys() - #get dependencies for each expression, load into graph - var_graph = graph() - for var in vars: var_graph.add_node(var) - for var, expr in exprs.iteritems(): - for dep in get_variable_dependencies(expr, vars): - var_graph.add_edge(dep, var) - return var_graph - -def sort_variables(exprs): - """ - Get a list of variables in order of dependencies. - @param exprs a mapping of variable name to expression - @return a list of variable names - @throws AssertionError circular dependencies - """ - var_graph = get_graph(exprs) - sorted_vars = list() - #determine dependency order - while var_graph.get_nodes(): - #get a list of nodes with no edges - indep_vars = filter(lambda var: not var_graph.get_edges(var), var_graph.get_nodes()) - assert indep_vars - #add the indep vars to the end of the list - sorted_vars.extend(sorted(indep_vars)) - #remove each edge-less node from the graph - for var in indep_vars: var_graph.remove_node(var) - return reversed(sorted_vars) - -if __name__ == '__main__': - for i in sort_variables({'x':'1', 'y':'x+1', 'a':'x+y', 'b':'y+1', 'c':'a+b+x+y'}): print i |