Improved Python target to become more PEP-8

CHANGELOG.md

@@ -2,10 +2,12 @@
 
 This file is used to document any relevant changes done to UniCC.
 
-## [main]
+## [v1.8]
 
 Current main branch.
 
+- Improved program module generator to support <true>- and <false>-settings
+- Target `python` updated to spaces instead of tabs and further improvements
 - Target `javascript` updated to more recent JS/ECMAScript6 features
 
 ## [v1.7]

targets/python.tlt

@@ -5,8 +5,6 @@
     <escape-sequence for="\" do="\\" />
     <escape-sequence for="&#x22;" do="\&#x22;" />
 
-    <code_localization />
-
     <vstack_def_type>any</vstack_def_type>
     <vstack_term_type>any</vstack_term_type>
     <vstack_union_att>@@value-type-id</vstack_union_att>
@@ -33,77 +31,67 @@
     <scan_action_set_symbol>pcb.sym = @@sym</scan_action_set_symbol>
 
     <defprod>
-        <col>@@production-number</col>
-        <col_sep>, </col_sep>
+        <col>        @@production-number,&#x0A;</col>
     </defprod>
 
     <acttab>
-        <row_start>        (</row_start>
-        <row_end>)</row_end>
-        <row_sep>,&#x0A;</row_sep>
-        <col>(@@symbol, @@action, @@index), </col>
-        <col_sep></col_sep>
+        <row_start>        (&#x0A;</row_start>
+        <row_end>        ),&#x0A;</row_end>
+        <col>            (@@symbol, @@action, @@index),&#x0A;</col>
     </acttab>
 
     <gotab>
-        <row_start>        (</row_start>
-        <row_end>)</row_end>
-        <row_sep>,&#x0A;</row_sep>
-        <col>(@@symbol, @@action, @@index), </col>
-        <col_sep></col_sep>
+        <row_start>        (&#x0A;</row_start>
+        <row_end>        ),&#x0A;</row_end>
+        <col>            (@@symbol, @@action, @@index),&#x0A;</col>
     </gotab>
 
     <dfa_select>
-        <col>@@machine</col>
-        <col_sep>, </col_sep>
+        <col>        @@machine,&#x0A;</col>
     </dfa_select>
 
     <dfa_char>
-        <col>(@@from, @@to)</col>
-        <col_sep>, </col_sep>
+        <col>        (@@from, @@to),&#x0A;</col>
     </dfa_char>
 
     <dfa_trans>
-        <col>@@goto</col>
-        <col_sep>, </col_sep>
+        <col>        @@goto,&#x0A;</col>
     </dfa_trans>
 
     <dfa_idx>
-        <row_start>        (</row_start>
-        <row_end>),</row_end>
-        <row_sep>&#x0A;</row_sep>
-        <col>@@index</col>
-        <col_sep>, </col_sep>
+        <row_start>        (&#x0A;</row_start>
+        <row_end>        ),&#x0A;</row_end>
+        <col>            @@index,&#x0A;</col>
     </dfa_idx>
 
     <dfa_accept>
-        <row_start>        (</row_start>
-        <row_end>),</row_end>
-        <row_sep>&#x0A;</row_sep>
-        <col>@@accept</col>
-        <col_sep>, </col_sep>
+        <row_start>        (&#x0A;</row_start>
+        <row_end>        ),&#x0A;</row_end>
+        <col>            @@accept,&#x0A;</col>
     </dfa_accept>
 
     <symbols>
-        <col>        ("@@symbol-name", "@@emit", @@type, @@lexem, @@whitespace, @@greedy)</col>
-        <col_sep>,&#x0A;</col_sep>
+        <col>        ("@@symbol-name", "@@emit", @@type, @@lexem, @@whitespace, @@greedy),&#x0A;</col>
     </symbols>
 
     <productions>
-        <col>        ("@@production", "@@emit", @@length, @@lhs)</col>
-        <col_sep>,&#x0A;</col_sep>
+        <col>        ("@@production", "@@emit", @@length, @@lhs),&#x0A;</col>
     </productions>
 
-    <file filename="@@basename.py">#!/usr/bin/python
-#-*- coding: utf-8 -*-
-
-# Parser module generated by unicc from @@filename.
+    <file filename="@@basename.py">#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# This parser module was generated by unicc from @@filename.
 # DO NOT EDIT THIS FILE MANUALLY, IT WILL GO AWAY!
+#
 @@prologue
 
-class @@prefixNode(object):
+class @@prefixNode:
     """
     This is an AST node.
+
+    Objects of this class are only created when the parser makes
+    use of the AST node syntax.
     """
 
     def __init__(self, emit = None, match = None, children = None):
@@ -128,6 +116,7 @@ class @@prefixNode(object):
 class @@prefixParseException(Exception):
     """
     Exception to be raised on a parse error.
+    TODO: This might be replaced by SyntaxError builtin.
     """
 
     def __init__(self, row, col, txt = None):
@@ -146,17 +135,25 @@ class @@prefixParseException(Exception):
         self.expecting = expecting
 
 
-class @@prefixParserToken(object):
+class _@@prefixToken:
+    """
+    Only used internally;
+    Represents a token on the stack.
+    """
     state = 0
     line = 0
     column = 0
-
     node = None
-
     @@value-type-definition
 
 
-class @@prefixParserControlBlock(object):
+class _@@prefixControlBlock:
+    """
+    Only used internally;
+    Represents the current parser state, and allows to
+    run multiple parser threads within one @@prefixParser.
+    """
+
     def __init__(self, input):
 
         # Stack
@@ -192,11 +189,13 @@ class @@prefixParserControlBlock(object):
 
         self.line = 1
         self.column = 1
-
         @@pcb
 
-
-class @@prefixParser(object):
+class @@prefixParser:
+    """
+    Implements a LALR-Parser for @@name.
+    Call @@prefixParser.parse() to start parsing a given string.
+    """
 
     # Actions
     _ERROR = 0
@@ -218,23 +217,27 @@ class @@prefixParser(object):
 @@goto-table
     )
 
-    _def_prod = (@@default-productions)
+    _def_prod = (
+@@default-productions
+    )
 
     # Lexical analysis
-    _dfa_select = (@@dfa-select)
+    _dfa_select = (
+@@dfa-select
+    )
     _dfa_index = (
 @@dfa-index
     )
-    _dfa_chars = (@@dfa-char)
-    _dfa_trans = (@@dfa-trans)
+    _dfa_chars = (
+@@dfa-char
+    )
+    _dfa_trans = (
+@@dfa-trans
+    )
     _dfa_accept = (
 @@dfa-accept
     )
 
-    # Parsing actions
-@@scan_actions
-@@actions
-
     # Parsing algorithm
 
     def _get_act(self, pcb):
@@ -394,10 +397,10 @@ class @@prefixParser(object):
             except NameError:
                 s = input(">")
 
-        pcb = @@prefixParserControlBlock(s)
+        pcb = _@@prefixControlBlock(s)
         pcb.act = self._SHIFT
 
-        pcb.tos = @@prefixParserToken()
+        pcb.tos = _@@prefixToken()
         pcb.stack.append(pcb.tos)
 
         while True:
@@ -438,9 +441,7 @@ class @@prefixParser(object):
                 # Handle AST nodes
                 if self._productions[pcb.idx][1]:
                     #print("%s = %s" % (self._productions[pcb.idx][0], self._productions[pcb.idx][1]))
-                    node = @@prefixNode(self._productions[pcb.idx][1],
-                                            children=cnodes)
-
+                    node = @@prefixNode(self._productions[pcb.idx][1], children=cnodes)
                 else:
                     node = None
 
@@ -457,7 +458,7 @@ class @@prefixParser(object):
 
                 self._get_go(pcb)
 
-                pcb.tos = @@prefixParserToken()
+                pcb.tos = _@@prefixToken()
                 pcb.stack.append(pcb.tos)
 
                 pcb.tos.symbol = self._symbols[pcb.lhs]
@@ -490,7 +491,7 @@ class @@prefixParser(object):
             if pcb.act &amp; self._SHIFT:
                 #print("SHIFT", pcb.sym, self._symbols[pcb.sym])
 
-                pcb.tos = @@prefixParserToken()
+                pcb.tos = _@@prefixToken()
                 pcb.stack.append(pcb.tos)
 
                 # Execute scanner actions, if existing.
@@ -526,7 +527,8 @@ class @@prefixParser(object):
             node = None
 
         return pcb.ret or node
-
+@@scan_actions
+@@actions
 @@epilogue
 
 if __name__ == "__main__":