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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.
This commit is contained in:
Georg Brandl
parent
04516611e7
commit
944f684ce6
11 changed files with 216 additions and 71 deletions
63
Python/ast.c
63
Python/ast.c
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@ -3009,27 +3009,18 @@ ast_for_try_stmt(struct compiling *c, const node *n)
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return TryFinally(body, finally, LINENO(n), n->n_col_offset, c->c_arena);
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}
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static expr_ty
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ast_for_with_var(struct compiling *c, const node *n)
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{
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REQ(n, with_var);
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return ast_for_expr(c, CHILD(n, 1));
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}
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/* with_stmt: 'with' test [ with_var ] ':' suite */
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/* with_item: test ['as' expr] */
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static stmt_ty
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ast_for_with_stmt(struct compiling *c, const node *n)
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ast_for_with_item(struct compiling *c, const node *n, asdl_seq *content)
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{
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expr_ty context_expr, optional_vars = NULL;
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int suite_index = 3; /* skip 'with', test, and ':' */
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asdl_seq *suite_seq;
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assert(TYPE(n) == with_stmt);
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context_expr = ast_for_expr(c, CHILD(n, 1));
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REQ(n, with_item);
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context_expr = ast_for_expr(c, CHILD(n, 0));
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if (!context_expr)
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return NULL;
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if (TYPE(CHILD(n, 2)) == with_var) {
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optional_vars = ast_for_with_var(c, CHILD(n, 2));
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if (NCH(n) == 3) {
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optional_vars = ast_for_expr(c, CHILD(n, 2));
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if (!optional_vars) {
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return NULL;
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@ -3037,17 +3028,47 @@ ast_for_with_stmt(struct compiling *c, const node *n)
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if (!set_context(c, optional_vars, Store, n)) {
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return NULL;
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}
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suite_index = 4;
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}
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suite_seq = ast_for_suite(c, CHILD(n, suite_index));
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if (!suite_seq) {
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return NULL;
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}
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return With(context_expr, optional_vars, suite_seq, LINENO(n),
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return With(context_expr, optional_vars, content, LINENO(n),
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n->n_col_offset, c->c_arena);
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}
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/* with_stmt: 'with' with_item (',' with_item)* ':' suite */
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static stmt_ty
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ast_for_with_stmt(struct compiling *c, const node *n)
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{
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int i;
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stmt_ty ret;
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asdl_seq *inner;
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REQ(n, with_stmt);
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/* process the with items inside-out */
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i = NCH(n) - 1;
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/* the suite of the innermost with item is the suite of the with stmt */
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inner = ast_for_suite(c, CHILD(n, i));
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if (!inner)
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return NULL;
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for (;;) {
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i -= 2;
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ret = ast_for_with_item(c, CHILD(n, i), inner);
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if (!ret)
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return NULL;
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/* was this the last item? */
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if (i == 1)
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break;
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/* if not, wrap the result so far in a new sequence */
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inner = asdl_seq_new(1, c->c_arena);
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if (!inner)
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return NULL;
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asdl_seq_SET(inner, 0, ret);
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}
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return ret;
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}
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static stmt_ty
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ast_for_classdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
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{
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@ -901,42 +901,43 @@ static arc arcs_41_0[1] = {
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{100, 1},
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};
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static arc arcs_41_1[1] = {
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{28, 2},
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{101, 2},
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};
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static arc arcs_41_2[2] = {
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{101, 3},
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{23, 4},
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{29, 1},
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{23, 3},
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};
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static arc arcs_41_3[1] = {
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{23, 4},
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{24, 4},
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};
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static arc arcs_41_4[1] = {
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{24, 5},
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{0, 4},
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};
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static arc arcs_41_5[1] = {
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{0, 5},
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};
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static state states_41[6] = {
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static state states_41[5] = {
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{1, arcs_41_0},
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{1, arcs_41_1},
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{2, arcs_41_2},
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{1, arcs_41_3},
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{1, arcs_41_4},
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{1, arcs_41_5},
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};
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static arc arcs_42_0[1] = {
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{80, 1},
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{28, 1},
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};
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static arc arcs_42_1[1] = {
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{84, 2},
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static arc arcs_42_1[2] = {
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{80, 2},
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{0, 1},
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};
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static arc arcs_42_2[1] = {
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{0, 2},
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{84, 3},
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};
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static state states_42[3] = {
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static arc arcs_42_3[1] = {
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{0, 3},
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};
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static state states_42[4] = {
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{1, arcs_42_0},
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{1, arcs_42_1},
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{2, arcs_42_1},
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{1, arcs_42_2},
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{1, arcs_42_3},
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};
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static arc arcs_43_0[1] = {
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{102, 1},
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@ -1877,10 +1878,10 @@ static dfa dfas[85] = {
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"\000\000\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000"},
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{296, "try_stmt", 0, 13, states_40,
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"\000\000\000\000\000\000\000\000\000\000\000\000\002\000\000\000\000\000\000\000\000\000"},
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{297, "with_stmt", 0, 6, states_41,
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{297, "with_stmt", 0, 5, states_41,
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"\000\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000"},
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{298, "with_var", 0, 3, states_42,
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"\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000\000\000"},
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{298, "with_item", 0, 4, states_42,
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"\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
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{299, "except_clause", 0, 5, states_43,
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"\000\000\000\000\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000"},
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{300, "suite", 0, 5, states_44,
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