Mercurial > cpython-lru_cache-weakref
diff Python/symtable.c @ 21325:8a26bb369f53 legacy-trunk
Add a comment explaining the st_symbols cache.
| author | Jeremy Hylton <jeremy@alum.mit.edu> |
|---|---|
| date | Mon, 10 Dec 2001 00:53:18 +0000 |
| parents | 4d5098cfa781 |
| children | 3aaf24b949df |
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--- a/Python/symtable.c Sun Dec 09 23:25:00 2001 +0000 +++ b/Python/symtable.c Mon Dec 10 00:53:18 2001 +0000 @@ -4,6 +4,20 @@ #include "graminit.h" #include "structmember.h" +/* The compiler uses this function to load a PySymtableEntry object + for a code block. Each block is loaded twice, once during the + symbol table pass and once during the code gen pass. Entries + created during the first pass are cached for the second pass, using + the st_symbols dictionary. + + The cache is keyed by st_nscopes. Each code block node in a + module's parse tree can be assigned a unique id based on the order + in which the nodes are visited by the compiler. This strategy + works so long as the symbol table and codegen passes visit the same + nodes in the same order. +*/ + + PyObject * PySymtableEntry_New(struct symtable *st, char *name, int type, int lineno) { @@ -14,7 +28,7 @@ if (k == NULL) goto fail; v = PyDict_GetItem(st->st_symbols, k); - if (v) /* XXX could check that name, type, lineno match */ { + if (v) { Py_DECREF(k); Py_INCREF(v); return v;
