Allow multiple context managers in one with statement, as proposed
in http://codereview.appspot.com/53094 and accepted by Guido.
The construct is transformed into multiple With AST nodes so that
there should be no problems with the semantics.
diff --git a/Python/ast.c b/Python/ast.c
index 5f369b6..271585f 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -3009,27 +3009,18 @@
return TryFinally(body, finally, LINENO(n), n->n_col_offset, c->c_arena);
}
-static expr_ty
-ast_for_with_var(struct compiling *c, const node *n)
-{
- REQ(n, with_var);
- return ast_for_expr(c, CHILD(n, 1));
-}
-
-/* with_stmt: 'with' test [ with_var ] ':' suite */
+/* with_item: test ['as' expr] */
static stmt_ty
-ast_for_with_stmt(struct compiling *c, const node *n)
+ast_for_with_item(struct compiling *c, const node *n, asdl_seq *content)
{
expr_ty context_expr, optional_vars = NULL;
- int suite_index = 3; /* skip 'with', test, and ':' */
- asdl_seq *suite_seq;
- assert(TYPE(n) == with_stmt);
- context_expr = ast_for_expr(c, CHILD(n, 1));
+ REQ(n, with_item);
+ context_expr = ast_for_expr(c, CHILD(n, 0));
if (!context_expr)
return NULL;
- if (TYPE(CHILD(n, 2)) == with_var) {
- optional_vars = ast_for_with_var(c, CHILD(n, 2));
+ if (NCH(n) == 3) {
+ optional_vars = ast_for_expr(c, CHILD(n, 2));
if (!optional_vars) {
return NULL;
@@ -3037,17 +3028,47 @@
if (!set_context(c, optional_vars, Store, n)) {
return NULL;
}
- suite_index = 4;
}
- suite_seq = ast_for_suite(c, CHILD(n, suite_index));
- if (!suite_seq) {
- return NULL;
- }
- return With(context_expr, optional_vars, suite_seq, LINENO(n),
+ return With(context_expr, optional_vars, content, LINENO(n),
n->n_col_offset, c->c_arena);
}
+/* with_stmt: 'with' with_item (',' with_item)* ':' suite */
+static stmt_ty
+ast_for_with_stmt(struct compiling *c, const node *n)
+{
+ int i;
+ stmt_ty ret;
+ asdl_seq *inner;
+
+ REQ(n, with_stmt);
+
+ /* process the with items inside-out */
+ i = NCH(n) - 1;
+ /* the suite of the innermost with item is the suite of the with stmt */
+ inner = ast_for_suite(c, CHILD(n, i));
+ if (!inner)
+ return NULL;
+
+ for (;;) {
+ i -= 2;
+ ret = ast_for_with_item(c, CHILD(n, i), inner);
+ if (!ret)
+ return NULL;
+ /* was this the last item? */
+ if (i == 1)
+ break;
+ /* if not, wrap the result so far in a new sequence */
+ inner = asdl_seq_new(1, c->c_arena);
+ if (!inner)
+ return NULL;
+ asdl_seq_SET(inner, 0, ret);
+ }
+
+ return ret;
+}
+
static stmt_ty
ast_for_classdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
{
diff --git a/Python/graminit.c b/Python/graminit.c
index ec2f421..2e3e9e8 100644
--- a/Python/graminit.c
+++ b/Python/graminit.c
@@ -901,42 +901,43 @@
{100, 1},
};
static arc arcs_41_1[1] = {
- {28, 2},
+ {101, 2},
};
static arc arcs_41_2[2] = {
- {101, 3},
- {23, 4},
+ {29, 1},
+ {23, 3},
};
static arc arcs_41_3[1] = {
- {23, 4},
+ {24, 4},
};
static arc arcs_41_4[1] = {
- {24, 5},
+ {0, 4},
};
-static arc arcs_41_5[1] = {
- {0, 5},
-};
-static state states_41[6] = {
+static state states_41[5] = {
{1, arcs_41_0},
{1, arcs_41_1},
{2, arcs_41_2},
{1, arcs_41_3},
{1, arcs_41_4},
- {1, arcs_41_5},
};
static arc arcs_42_0[1] = {
- {80, 1},
+ {28, 1},
};
-static arc arcs_42_1[1] = {
- {84, 2},
+static arc arcs_42_1[2] = {
+ {80, 2},
+ {0, 1},
};
static arc arcs_42_2[1] = {
- {0, 2},
+ {84, 3},
};
-static state states_42[3] = {
+static arc arcs_42_3[1] = {
+ {0, 3},
+};
+static state states_42[4] = {
{1, arcs_42_0},
- {1, arcs_42_1},
+ {2, arcs_42_1},
{1, arcs_42_2},
+ {1, arcs_42_3},
};
static arc arcs_43_0[1] = {
{102, 1},
@@ -1877,10 +1878,10 @@
"\000\000\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000"},
{296, "try_stmt", 0, 13, states_40,
"\000\000\000\000\000\000\000\000\000\000\000\000\002\000\000\000\000\000\000\000\000\000"},
- {297, "with_stmt", 0, 6, states_41,
+ {297, "with_stmt", 0, 5, states_41,
"\000\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000"},
- {298, "with_var", 0, 3, states_42,
- "\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000\000\000"},
+ {298, "with_item", 0, 4, states_42,
+ "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
{299, "except_clause", 0, 5, states_43,
"\000\000\000\000\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000"},
{300, "suite", 0, 5, states_44,