summaryrefslogtreecommitdiff
path: root/ext/ply/test/yacc_misplaced.py
diff options
context:
space:
mode:
Diffstat (limited to 'ext/ply/test/yacc_misplaced.py')
-rw-r--r--ext/ply/test/yacc_misplaced.py68
1 files changed, 68 insertions, 0 deletions
diff --git a/ext/ply/test/yacc_misplaced.py b/ext/ply/test/yacc_misplaced.py
new file mode 100644
index 000000000..9159b0109
--- /dev/null
+++ b/ext/ply/test/yacc_misplaced.py
@@ -0,0 +1,68 @@
+# -----------------------------------------------------------------------------
+# yacc_misplaced.py
+#
+# A misplaced | in grammar rules
+# -----------------------------------------------------------------------------
+import sys
+
+if ".." not in sys.path: sys.path.insert(0,"..")
+import ply.yacc as yacc
+
+from calclex import tokens
+
+# Parsing rules
+precedence = (
+ ('left','PLUS','MINUS'),
+ ('left','TIMES','DIVIDE'),
+ ('right','UMINUS'),
+ )
+
+# dictionary of names
+names = { }
+
+def p_statement_assign(t):
+ 'statement : NAME EQUALS expression'
+ names[t[1]] = t[3]
+
+def p_statement_expr(t):
+ 'statement : expression'
+ print(t[1])
+
+def p_expression_binop(t):
+ ''' | expression PLUS expression
+ | expression MINUS expression
+ | expression TIMES expression
+ | expression DIVIDE expression'''
+ if t[2] == '+' : t[0] = t[1] + t[3]
+ elif t[2] == '-': t[0] = t[1] - t[3]
+ elif t[2] == '*': t[0] = t[1] * t[3]
+ elif t[2] == '/': t[0] = t[1] / t[3]
+
+def p_expression_uminus(t):
+ 'expression : MINUS expression %prec UMINUS'
+ t[0] = -t[2]
+
+def p_expression_group(t):
+ 'expression : LPAREN expression RPAREN'
+ t[0] = t[2]
+
+def p_expression_number(t):
+ 'expression : NUMBER'
+ t[0] = t[1]
+
+def p_expression_name(t):
+ 'expression : NAME'
+ try:
+ t[0] = names[t[1]]
+ except LookupError:
+ print("Undefined name '%s'" % t[1])
+ t[0] = 0
+
+def p_error(t):
+ print("Syntax error at '%s'" % t.value)
+
+yacc.yacc()
+
+
+
+