def test_diag(self):
with unittest.mock.patch('liblet.antlr.warn') as mock_warn:
Ambig = ANTLR(r"""
grammar Ambig;
stat: expr ';' | ID '(' ')' ';' ;
expr: ID '(' ')' | INT ;
INT : [0-9]+ ;
ID : [a-zA-Z]+ ;
WS : [ \t\r\n]+ -> skip ;
""")
text = 'f();'
Ambig.context(text, 'stat', diag=True)
args, kwargs = mock_warn.call_args
errs = "line 1:3 reportAttemptingFullContext d=0 (stat), input='f();'\nline 1:3 reportAmbiguity d=0 (stat): ambigAlts={1, 2}, input='f();'"
self.assertEqual(args[0], errs)
def test_trace(self):
buf = StringIO()
with redirect_stdout(buf):
Ambig = ANTLR(r"""
grammar Ambig;
stat: expr ';' | ID '(' ')' ';' ;
expr: ID '(' ')' | INT ;
INT : [0-9]+ ;
ID : [a-zA-Z]+ ;
WS : [ \t\r\n]+ -> skip ;
""")
text = 'f();'
Ambig.context(text, 'stat', trace=True)
trace = dedent("""
enter stat, LT(1)=f
enter expr, LT(1)=f
consume [@0,0:0='f',<5>,1:0] rule expr
consume [@1,1:1='(',<2>,1:1] rule expr
consume [@2,2:2=')',<3>,1:2] rule expr
exit expr, LT(1)=;
consume [@3,3:3=';',<1>,1:3] rule stat
exit stat, LT(1)=<EOF>
""")[1:] # remove first blank line
self.assertEqual(buf.getvalue(), trace)
def test_tree_str(self):
Bad = ANTLR(r"""
grammar Bad ;
start: expr ;
expr: ID | expr OP ID | expr '*' ID;
OP: '+' | '-' ;
ID: [a-z];
""")
tree = Bad.context(
'z-a+a*x',
'start',
as_string=True,
)
self.assertEqual(tree,
"(start (expr (expr (expr (expr z) - a) + a) * x))")