Add value parser + use it for the gui

replaces eval which is used so far

Change-Id: Ie5ff8c82175786e233d52bc0faac4e72e3bc27e9
Reviewed-on: https://forge.frm2.tum.de/review/17271
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop/parse.py

@@ -0,0 +1,167 @@
+#  -*- coding: utf-8 -*-
+# *****************************************************************************
+#
+# This program 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.
+#
+# This program 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.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
+#
+# *****************************************************************************
+"""parser. used for config files and the gui
+
+can't use ast.literal_eval as it can't handle enums :(
+
+parsing rules:
+(...) -> tuple
+[...] -> tuple
+{text:...} -> dict
+{text=...} -> dict
+..., ... -> tuple
+digits -> float or int (try int, if it fails: take float)
+text -> string
+'text' -> string
+"text" -> string
+
+further convertions are done by the validator of the datatype....
+"""
+
+from collections import OrderedDict
+
+
+class Parser(object):
+    # all parsing methods return (parsed value, remaining string)
+    # or (None, remaining_text) if parsing error
+
+    def parse_number(self, text):
+        text = text.strip()
+        l = 1
+        number = None
+        while l <= len(text):
+            try:
+                number = float(text[:l])
+                length = l
+                l += 1
+            except ValueError:
+                if text[l - 1] in u'eE+-':
+                    l += 1
+                    continue
+                if number is None:
+                    return None, text
+                try:
+                    return int(text[:length]), text[length:]
+                except ValueError:
+                    return number, text[length:]
+        return number, ''
+
+    def parse_string(self, orgtext):
+        # handle quoted and unquoted strings correctly
+        text = orgtext.strip()
+        if text[0] in (u'"', u"'"):
+            # quoted string
+            quote = text[0]
+            idx = 0
+
+            while True:
+                idx = text.find(quote, idx + 1)
+                if idx == -1:
+                    return None, orgtext
+                # check escapes!
+                if text[idx - 1] == u'\\':
+                    continue
+                return text[1:idx], text[idx + 1:]
+
+        # unquoted strings are terminated by comma or whitespace
+        idx = 0
+        while idx < len(text):
+            if text[idx] in u'\x09 ,.;:()[]{}<>-+*/\\!"§$%&=?#~+*\'´`^°|-':
+                break
+            idx += 1
+        return text[:idx] or None, text[idx:]
+
+    def parse_tuple(self, orgtext):
+        text = orgtext.strip()
+        bra = text[0]
+        if bra not in u'([<':
+            return None, orgtext
+        # convert to closing bracket
+        bra = u')]>'[u'([<'.index(bra)]
+        reslist = []
+        # search for cosing bracket, collecting results
+        text = text[1:]
+        while text:
+            if bra not in text:
+                return None, text
+            res, rem = self.parse_sub(text)
+            if res is None:
+                return None, text
+            reslist.append(res)
+            if rem[0] == bra:
+                return tuple(reslist), rem[1:]
+            # eat separator
+            if rem[0] in u',;':
+                text = rem[1:]
+            else:
+                return None, rem
+        return None, orgtext
+
+    def parse_dict(self, orgtext):
+        text = orgtext.strip()
+        if text[0] != u'{':
+            return None, orgtext
+        # keep ordering
+        result = OrderedDict()
+        # search for cosing bracket, collecting results
+        # watch for key=value or key:value pairs, separated by ,
+        text = text[1:]
+        while u'}' in text:
+            # first part is always a string
+            key, rem = self.parse_string(text)
+            if not key:
+                return None, orgtext
+            if rem[0] not in u':=':
+                return None, rem
+            # eat separator
+            text = rem[1:]
+            value, rem = self.parse_sub(text)
+            if not value:
+                return None, orgtext
+            result[key] = value
+            if rem[0] == u'}':
+                return result, rem[1:]
+
+            if rem[0] not in u',;':
+                return None, rem
+            # eat separator
+            text = rem[1:]
+        return None, text
+
+    def parse_sub(self, orgtext):
+        text = orgtext.strip()
+        if not text:
+            return None, orgtext
+        if text[0] in u'+-.0123456789':
+            return self.parse_number(orgtext)
+        elif text[0] == u'{':
+            return self.parse_dict(orgtext)
+        elif text[0] in u'([<':
+            return self.parse_tuple(orgtext)
+        return self.parse_string(orgtext)
+
+    def parse(self, orgtext):
+        print "parsing %r" % orgtext
+        res, rem = self.parse_sub(orgtext)
+        if rem and rem[0] in u',;':
+            return self.parse_sub(u'[%s]' % orgtext)
+        return res, rem