circuitpython/tests/basics/string_fstring.py
Jim Mussared fb8792c095 py/lexer: Wrap in parenthesis all f-string arguments passed to format.
This is important for literal tuples, e.g.

    f"{a,b,}, {c}" --> "{}".format((a,b), (c),)

which would otherwise result in either a syntax error or the wrong result.

Fixes issue #9635.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2023-01-20 17:54:32 +11:00

64 lines
1.4 KiB
Python

def f():
return 4
def g(_):
return 5
def h():
return 6
print(f'no interpolation')
print(f"no interpolation")
print(f"""no interpolation""")
x, y = 1, 2
print(f'{x}')
print(f'{x:08x}')
print(f'a {x} b {y} c')
print(f'a {x:08x} b {y} c')
print(f'a {"hello"} b')
print(f'a {f() + g("foo") + h()} b')
def foo(a, b):
return f'{x}{y}{a}{b}'
print(foo(7, 8))
# ':' character within {...} that should not be interpreted as format specifiers.
print(f"a{[0,1,2][0:2]}")
print(f"a{[0,15,2][0:2][-1]:04x}")
# Nested '{' and '}' characters.
print(f"a{ {0,1,2}}")
# PEP-0498 specifies that '\\' and '#' must be disallowed explicitly, whereas
# MicroPython relies on the syntax error as a result of the substitution.
print(f"\\")
print(f'#')
try:
eval("f'{\}'")
except SyntaxError:
print('SyntaxError')
try:
eval("f'{#}'")
except SyntaxError:
print('SyntaxError')
# PEP-0498 specifies that handling of double braces '{{' or '}}' should
# behave like str.format.
print(f'{{}}')
print(f'{{{4*10}}}', '{40}')
# A single closing brace, unlike str.format should raise a syntax error.
# MicroPython instead raises ValueError at runtime from the substitution.
try:
eval("f'{{}'")
except (ValueError, SyntaxError):
# MicroPython incorrectly raises ValueError here.
print('SyntaxError')
# Allow literal tuples
print(f"a {1,} b")
print(f"a {x,y,} b")
print(f"a {x,1} b")