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Implement PEP 238 in its (almost) full glory.

Browse source 
This introduces:

- A new operator // that means floor division (the kind of division
  where 1/2 is 0).

- The "future division" statement ("from __future__ import division)
  which changes the meaning of the / operator to implement "true
  division" (where 1/2 is 0.5).

- New overloadable operators __truediv__ and __floordiv__.

- New slots in the PyNumberMethods struct for true and floor division,
  new abstract APIs for them, new opcodes, and so on.

I emphasize that without the future division statement, the semantics
of / will remain unchanged until Python 3.0.

Not yet implemented are warnings (default off) when / is used with int
or long arguments.

This has been on display since 7/31 as SF patch #443474.

Flames to /dev/null.
This commit is contained in:
Guido van Rossum 2001-08-08 05:00:18 +00:00
parent 074c9d2b20
commit 4668b000a1
19 changed files with 476 additions and 226 deletions
Download patch file Download diff file Expand all files Collapse all files

29
Python/compile.c
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@ -1874,14 +1874,20 @@ com_term(struct compiling *c, node *n)
op = BINARY_MULTIPLY;
break;
case SLASH:
op = BINARY_DIVIDE;
if (c->c_flags & CO_FUTURE_DIVISION)
op = BINARY_TRUE_DIVIDE;
else
op = BINARY_DIVIDE;
break;
case PERCENT:
op = BINARY_MODULO;
break;
case DOUBLESLASH:
op = BINARY_FLOOR_DIVIDE;
break;
default:
com_error(c, PyExc_SystemError,
"com_term: operator not *, / or %");
"com_term: operator not *, /, // or %");
op = 255;
}
com_addbyte(c, op);
@ -2475,7 +2481,14 @@ com_augassign(struct compiling *c, node *n)
switch (STR(CHILD(CHILD(n, 1), 0))[0]) {
case '+': opcode = INPLACE_ADD; break;
case '-': opcode = INPLACE_SUBTRACT; break;
case '/': opcode = INPLACE_DIVIDE; break;
case '/':
if (STR(CHILD(CHILD(n, 1), 0))[1] == '/')
opcode = INPLACE_FLOOR_DIVIDE;
else if (c->c_flags & CO_FUTURE_DIVISION)
opcode = INPLACE_TRUE_DIVIDE;
else
opcode = INPLACE_DIVIDE;
break;
case '%': opcode = INPLACE_MODULO; break;
case '<': opcode = INPLACE_LSHIFT; break;
case '>': opcode = INPLACE_RSHIFT; break;
@ -3945,7 +3958,8 @@ jcompile(node *n, char *filename, struct compiling *base,
if (base->c_nested
|| (sc.c_symtable->st_cur->ste_type == TYPE_FUNCTION))
sc.c_nested = 1;
sc.c_flags |= base->c_flags & CO_GENERATOR_ALLOWED;
sc.c_flags |= base->c_flags & (CO_GENERATOR_ALLOWED |
CO_FUTURE_DIVISION);
} else {
sc.c_private = NULL;
sc.c_future = PyNode_Future(n, filename);
@ -3963,6 +3977,11 @@ jcompile(node *n, char *filename, struct compiling *base,
sc.c_future->ff_generators = 1;
else if (sc.c_future->ff_generators)
flags->cf_flags |= PyCF_GENERATORS;
if (flags->cf_flags & PyCF_DIVISION)
sc.c_future->ff_division = 1;
else if (sc.c_future->ff_division)
flags->cf_flags |= PyCF_DIVISION;
}
if (symtable_build(&sc, n) < 0) {
com_free(&sc);
@ -4437,6 +4456,8 @@ symtable_update_flags(struct compiling *c, PySymtableEntryObject *ste,
c->c_flags |= CO_NESTED;
if (c->c_future->ff_generators)
c->c_flags |= CO_GENERATOR_ALLOWED;
if (c->c_future->ff_division)
c->c_flags |= CO_FUTURE_DIVISION;
}
if (ste->ste_generator)
c->c_flags |= CO_GENERATOR;