Use Node class from monkey.util in parser

Also simplify rules for list expressions.

2 files changed, 27 insertions, 45 deletions

diff --git a/monkey/graph.py b/monkey/graph.py
index 5bf78ec..3e1d3a2 100644
--- a/monkey/graph.py
+++ b/monkey/graph.py
@@ -1,10 +1,10 @@
 #!/usr/bin/python3
 
 class Node(object):
-    def __init__(self, data):
+    def __init__(self, data, eout=None):
         self.data = data
         self.ein = []
-        self.eout = []
+        self.eout = eout if eout else []
 
     # (Re-)insert a child node [target] to [self] at index [idx] (or as the
     # rightmost child if index is not given). Also append [self] to the list of
diff --git a/prolog/parser.py b/prolog/parser.py
index ec42b5b..456539f 100644
--- a/prolog/parser.py
+++ b/prolog/parser.py
@@ -3,6 +3,7 @@
 import ply.yacc as yacc
 from .lexer import operators, tokens
 from .util import Token
+from monkey.graph import Node
 
 # PARSER
 precedence = (
@@ -20,22 +21,9 @@ precedence = (
     ('nonassoc', 'LBRACKET', 'RBRACKET', 'LPAREN', 'RPAREN', 'COMMA', 'SEMI', 'PIPE', 'LBRACE', 'RBRACE')
 )
 
-class Node:
-    def __init__(self, type, children=None, data=None):
-         self.type = type
-         self.data = data
-         self.children = children if children else []
-
-    def __str__(self):
-        val = self.type
-        if self.children:
-            val += ' ' + ' '.join([str(c) for c in self.children])
-            val = '({})'.format(val)
-        return val
-
 def make_token(p, n):
     lextoken = p.slice[n]
-    return Token(lextoken.type, lextoken.value, lextoken.lexpos)
+    return Node(data=Token(lextoken.type, lextoken.value, lextoken.lexpos))
 
 def p_text_empty(p):
     'text : '
@@ -43,7 +31,7 @@ def p_text_empty(p):
 def p_text_clause(p):
     'text : text clause'
     p[0] = p[1]
-    p[0].children.append(p[2])
+    p[0].eout.append(p[2])
 
 def p_clause_head(p):
     'clause : head PERIOD'
@@ -53,7 +41,7 @@ def p_clause_rule(p):
     p[0] = Node('clause', [p[1], make_token(p, 2), p[3], make_token(p, 4)])
 def p_clause_error(p):
     'clause : error PERIOD'
-    p[0] = Node('error')
+    p[0] = Node('clause', [Node('error'), make_token(p, 2)])
 
 def p_head(p):
     'head : term'
@@ -64,12 +52,12 @@ def p_or_single(p):
     p[0] = p[1]
 def p_or_if(p):
     'or : or SEMI if'
-    if p[1].type == 'or':
+    if p[1].data == 'or':
         p[0] = p[1]
     else:
         p[0] = Node('or', [p[1]])
-    p[0].children.append(make_token(p, 2))
-    p[0].children.append(p[3])
+    p[0].eout.append(make_token(p, 2))
+    p[0].eout.append(p[3])
 
 def p_if_single(p):
     'if : and'
@@ -83,18 +71,18 @@ def p_and_single(p):
     p[0] = p[1]
 def p_and_term(p):
     'and : and COMMA term'
-    if p[1].type == 'and':
+    if p[1].data == 'and':
         p[0] = p[1]
     else:
         p[0] = Node('and', [p[1]])
-    p[0].children.append(make_token(p, 2))
-    p[0].children.append(p[3])
+    p[0].eout.append(make_token(p, 2))
+    p[0].eout.append(p[3])
 
 def p_term_functor(p):
     'term : functor LPAREN args RPAREN'
     # No whitespace allowed between functor and LPAREN.
     t2 = make_token(p, 2)
-    if p[1].children[0].pos + len(p[1].children[0].val) < t2.pos:
+    if p[1].eout[0].data.pos + len(p[1].eout[0].data.val) < t2.data.pos:
         raise SyntaxError('whitespace before ' + str(t2))
     p[0] = Node('term', [p[1], t2, p[3], make_token(p, 4)])
 def p_term_or(p):
@@ -152,31 +140,25 @@ def p_args_single(p):
 def p_args_term(p):
     'args : args COMMA term'
     p[0] = p[1]
-    p[0].children.append(make_token(p, 2))
-    p[0].children.append(p[3])
-
-def p_list_empty(p):
-    'list : LBRACKET RBRACKET'
-    p[0] = Node('list', [make_token(p, 1), make_token(p, 2)])
-def p_list_term(p):
-    'list : LBRACKET listexpr RBRACKET'
-    p[0] = Node('list', [make_token(p, 1), p[2], make_token(p, 3)])
-def p_listexpr_single(p):
-    'listexpr : term'
-    p[0] = Node('listexpr', [p[1]])
-def p_listexpr_term(p):
-    'listexpr : term COMMA listexpr'
-    p[0] = Node('listexpr', [p[1], make_token(p, 2), p[3]])
-def p_listexpr_pipe(p):
-    'listexpr : term PIPE term'
-    p[0] = Node('listexpr', [p[1], make_token(p, 2), p[3]])
+    p[0].eout.append(make_token(p, 2))
+    p[0].eout.append(p[3])
+
+def p_list(p):
+    'list : LBRACKET args RBRACKET'
+    p[0] = Node('list', [make_token(p, 1)] + p[2].eout + [make_token(p, 3)])
+def p_list_tail(p):
+    'list : LBRACKET args PIPE term RBRACKET'
+    p[0] = Node('list', [make_token(p, 1)] + p[2].eout + [make_token(p, 3), p[4], make_token(p, 5)])
 
 def p_functor(p):
     'functor : NAME'
     p[0] = Node('functor', [make_token(p, 1)])
 
-def p_error(p):
-    print('Syntax error in input: ' + str(p))
+def p_error(t):
+    if t is None:
+        print('unexpected end of file')
+    else:
+        print('{}: unexpected {}'.format(t.lexpos, t.value))
 
 parser = yacc.yacc()