Commit 29e9db0c authored by Damien George's avatar Damien George
Browse files

py: Fix compiler to handle lambdas used as default arguments.

Addresses issue #1709.
parent bb7f5b55
......@@ -662,6 +662,13 @@ STATIC void compile_funcdef_lambdef_param(compiler_t *comp, mp_parse_node_t pn)
}
STATIC void compile_funcdef_lambdef(compiler_t *comp, scope_t *scope, mp_parse_node_t pn_params, pn_kind_t pn_list_kind) {
// When we call compile_funcdef_lambdef_param below it can compile an arbitrary
// expression for default arguments, which may contain a lambda. The lambda will
// call here in a nested way, so we must save and restore the relevant state.
bool orig_have_star = comp->have_star;
uint16_t orig_num_dict_params = comp->num_dict_params;
uint16_t orig_num_default_params = comp->num_default_params;
// compile default parameters
comp->have_star = false;
comp->num_dict_params = 0;
......@@ -681,6 +688,11 @@ STATIC void compile_funcdef_lambdef(compiler_t *comp, scope_t *scope, mp_parse_n
// make the function
close_over_variables_etc(comp, scope, comp->num_default_params, comp->num_dict_params);
// restore state
comp->have_star = orig_have_star;
comp->num_dict_params = orig_num_dict_params;
comp->num_default_params = orig_num_default_params;
}
// leaves function object on stack
......
# testing default args to a function
def fun1(val=5):
print(val)
......@@ -18,3 +20,10 @@ try:
fun2(1, 2, 3, 4)
except TypeError:
print("TypeError")
# lambda as default arg (exposes nested behaviour in compiler)
def f(x=lambda:1):
return x()
print(f())
print(f(f))
print(f(lambda:2))
......@@ -57,3 +57,10 @@ def f(a, *b, c):
f(1, c=2)
f(1, 2, c=3)
f(a=1, c=3)
# lambda as kw-only arg (exposes nested behaviour in compiler)
def f(*, x=lambda:1):
return x()
print(f())
print(f(x=f))
print(f(x=lambda:2))
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