Parameter parser helper to replace eval of env variable (#89)

src/hunter/paramparser.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+
+testdata = """
+stdlib=False
+~Q(kind="line"),~Q(module_in=["six","pkg_resources"]),~Q(filename=""),stdlib=False
+stdlib=False,Q(filename_contains='venv')
+"""
+
+
+class ParamParser:
+    """
+    Splits a param string into list of strings.
+
+    The logic is basically to split by commas, ignoring commas inside parens.
+    """
+    def parse(self, string):
+        # make object variables for debugging
+        self.raw = string
+        self.parsed = []
+        if not self.raw:
+            pass  # print("empty param string")
+            return self.parsed
+
+        self.parsed = []
+        self.current = ''
+        self.embrace = False  # True if parsing inside parens
+        # scan for either comma or brace
+        for i in self.raw:
+            if self.embrace:
+                self.current += i
+                if i == ')':
+                    self.embrace = False
+                continue
+
+            # from here we are not in parens (yet)
+            if i == '(':
+                self.current += i
+                self.embrace = True
+            elif i == ',':
+                if not self.current:
+                    pass  # print("hey, that's a missing param between commas")
+                else:
+                    self.parsed.append(self.current)
+                    self.current = ''
+            else:  # i is not ( or ,
+                self.current += i
+
+        else:
+            if not self.current:
+                pass  # print("empty param after last comma")
+            else:
+                self.parsed.append(self.current)
+                self.current = ''
+        return self.parsed
+
+
+if __name__ == '__main__':
+    for line in testdata.splitlines():
+        print(line)
+        params = ParamParser().parse(line)
+        if not params:
+            print("  %s" % params)
+        else:
+            for param in params:
+                print("  %s" % param)