ref: 1fe3143e4c43ce2c74e0cfdd70b1bd556bbb9e1b
dir: /sys/src/cmd/python/Python/future.c/
#include "Python.h" #include "Python-ast.h" #include "node.h" #include "token.h" #include "graminit.h" #include "code.h" #include "compile.h" #include "symtable.h" #define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined" static int future_check_features(PyFutureFeatures *ff, stmt_ty s, const char *filename) { int i; asdl_seq *names; assert(s->kind == ImportFrom_kind); names = s->v.ImportFrom.names; for (i = 0; i < asdl_seq_LEN(names); i++) { alias_ty name = (alias_ty)asdl_seq_GET(names, i); const char *feature = PyString_AsString(name->name); if (!feature) return 0; if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) { continue; } else if (strcmp(feature, FUTURE_GENERATORS) == 0) { continue; } else if (strcmp(feature, FUTURE_DIVISION) == 0) { ff->ff_features |= CO_FUTURE_DIVISION; } else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) { ff->ff_features |= CO_FUTURE_ABSOLUTE_IMPORT; } else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) { ff->ff_features |= CO_FUTURE_WITH_STATEMENT; } else if (strcmp(feature, "braces") == 0) { PyErr_SetString(PyExc_SyntaxError, "not a chance"); PyErr_SyntaxLocation(filename, s->lineno); return 0; } else { PyErr_Format(PyExc_SyntaxError, UNDEFINED_FUTURE_FEATURE, feature); PyErr_SyntaxLocation(filename, s->lineno); return 0; } } return 1; } static int future_parse(PyFutureFeatures *ff, mod_ty mod, const char *filename) { int i, found_docstring = 0, done = 0, prev_line = 0; static PyObject *future; if (!future) { future = PyString_InternFromString("__future__"); if (!future) return 0; } if (!(mod->kind == Module_kind || mod->kind == Interactive_kind)) return 1; /* A subsequent pass will detect future imports that don't appear at the beginning of the file. There's one case, however, that is easier to handl here: A series of imports joined by semi-colons, where the first import is a future statement but some subsequent import has the future form but is preceded by a regular import. */ for (i = 0; i < asdl_seq_LEN(mod->v.Module.body); i++) { stmt_ty s = (stmt_ty)asdl_seq_GET(mod->v.Module.body, i); if (done && s->lineno > prev_line) return 1; prev_line = s->lineno; /* The tests below will return from this function unless it is still possible to find a future statement. The only things that can precede a future statement are another future statement and a doc string. */ if (s->kind == ImportFrom_kind) { if (s->v.ImportFrom.module == future) { if (done) { PyErr_SetString(PyExc_SyntaxError, ERR_LATE_FUTURE); PyErr_SyntaxLocation(filename, s->lineno); return 0; } if (!future_check_features(ff, s, filename)) return 0; ff->ff_lineno = s->lineno; } else done = 1; } else if (s->kind == Expr_kind && !found_docstring) { expr_ty e = s->v.Expr.value; if (e->kind != Str_kind) done = 1; else found_docstring = 1; } else done = 1; } return 1; } PyFutureFeatures * PyFuture_FromAST(mod_ty mod, const char *filename) { PyFutureFeatures *ff; ff = (PyFutureFeatures *)PyObject_Malloc(sizeof(PyFutureFeatures)); if (ff == NULL) { PyErr_NoMemory(); return NULL; } ff->ff_features = 0; ff->ff_lineno = -1; if (!future_parse(ff, mod, filename)) { PyObject_Free(ff); return NULL; } return ff; }