def test_epsilon():
grammar = """
S ::= "b" A "d"
A ::= "c"
|
"""
lrp = LRParser(grammar, 1)
assert lrp.check("b c d") == True
assert lrp.check("b d") == True
def test_epsilon2():
grammar = """
S ::= A B "c"
A ::= "a"
B ::= "b"
|
"""
lrp = LRParser(grammar, LR0)
assert lrp.check("a b c") == True
assert lrp.check("a c") == True
assert lrp.check("a b b") == False
lrp = LRParser(grammar, LALR)
assert lrp.check("a b c") == True
assert lrp.check("a c") == True
assert lrp.check("a b b") == False
def test_calc2():
grammar = """
E ::= T
| E "+" T
T ::= P
| T "*" P
P ::= "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
"""
lrp = LRParser(grammar, 0)
assert lrp.check("1 + 2") == True
assert lrp.check("1 + 2 * 3") == True
assert lrp.check("1 * 2 * 3 + 4") == True
lrp = LRParser(grammar, 1)
assert lrp.check("1 + 2") == True
assert lrp.check("1 + 2 * 3") == True
assert lrp.check("1 * 2 * 3 + 4") == True
def notest_small_language():
grammar = """
program ::= ws class program
ws ::= ws ws_char
|
ws_char ::= "\n" | "\t" | "\r"
id ::= id_char id
|
id_char ::= "a"|"b"|"c"|"d"|"e"|"f"|"g"|"h"|"i"|"j"|"k"|"l"|"m"|"n"|"o"|"p"|"q"|"r"|"s"|"t"|"u"|"v"|"w"|"x"|"y"|"z"
|
class ::= "class" ws id ws "{" functions "}"
functions ::= ws function ws functions
|
function ::= "function" ws id ws "{" func_body "}"
func_body ::= ws
"""
lrp = LRParser(grammar, LR0)
assert lrp.check("""class test { function hello { } }""") == True
lrp = LRParser(grammar, LALR)
assert lrp.check("""
class test {
function hello {
}
}
""") == True
def test_calc1():
grammar = """
E ::= P
| E "+" P
P ::= "1" | "2"
"""
lrp = LRParser(grammar, 0)
assert lrp.check("1") == True
assert lrp.check("1 + 2") == True
print("NOW WITH LR(1)")
lrp = LRParser(grammar, 1)
assert lrp.check("1 + 2") == True
def notest_ast():
lrp = LRParser(grammar)
lrp.check("1 + 2 * 3")
ast = lrp.get_ast()
AST(
Node(E, [
Node(E, [Node(T, [Node(P, [n1])])]),
Node(plus, []),
Node(T, [
Node(T, [Node(P, [n2])]),
Node(mul, []),
Node(P, [n3])
])
])
) == ast
lrp.check("1 + 2 * 1")
ast2 = lrp.get_ast()
def test_input2():
lrp = LRParser(grammar, 1)
assert lrp.check("a b d") == True
assert lrp.check("a c d") == True
assert lrp.check("a a d") == False
def test_recursion2():
grammar = """
S ::= "b" A
A ::= S
|
"""
lrp = LRParser(grammar, LR0)
assert lrp.check("b b b b b b b b b b b") == True
assert lrp.check("b b") == True
assert lrp.check("b") == True
assert lrp.check("") == False
lrp = LRParser(grammar, LALR)
assert lrp.check("b b b b b b b b b b b") == True
assert lrp.check("b b") == True
assert lrp.check("b") == True
assert lrp.check("") == False
