xo-reader: feat: handle parenthesized expressions
This commit is contained in:
parent
37268113fb
commit
6ff2ac97b0
3 changed files with 277 additions and 34 deletions
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@ -36,6 +36,12 @@ namespace xo {
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return "def_3";
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case exprstatetype::def_4:
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return "def_4";
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case exprstatetype::def_5:
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return "def_5";
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case exprstatetype::lparen_0:
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return "lparen_0";
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case exprstatetype::lparen_1:
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return "lparen_1";
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case exprstatetype::expect_rhs_expression:
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return "expect_rhs_expression";
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case exprstatetype::expect_symbol:
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@ -62,12 +68,15 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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/* note for def_4:
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* rhs could certainly be a function body that contains
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* nested defines; but then immediately-enclosing-exprstate
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* would be a block
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*/
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return false;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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case exprstatetype::expect_rhs_expression:
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return false;
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case exprstatetype::expect_symbol:
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@ -93,8 +102,11 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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return false;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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case exprstatetype::expect_rhs_expression:
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/* treat symbol as variable name */
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return true;
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@ -131,6 +143,9 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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case exprstatetype::expect_rhs_expression:
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/* rhs-expressions (or expressions for that matter)
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* may not begin with a colon
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@ -160,6 +175,11 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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return false;
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case exprstatetype::def_5:
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return true;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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case exprstatetype::expect_rhs_expression:
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case exprstatetype::expect_symbol:
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case exprstatetype::expect_type:
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@ -206,7 +226,10 @@ namespace xo {
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return true;
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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case exprstatetype::expect_rhs_expression:
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/* rhs-expressions (or expressions for that matter)
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* may not begin with singleassign '='
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@ -236,6 +259,13 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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return false;
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case exprstatetype::lparen_0:
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return true;
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case exprstatetype::lparen_1:
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return false;
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case exprstatetype::expect_rhs_expression:
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@ -257,7 +287,6 @@ namespace xo {
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return false;
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}
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#ifdef NOT_YET
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bool
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exprstate::admits_leftparen() const {
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switch (exs_type_) {
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@ -278,6 +307,7 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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/* input like
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* def foo : f64 = (
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* ^ ^ ^ ^ ^
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@ -291,6 +321,12 @@ namespace xo {
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*/
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return false;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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/* unreachable */
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assert(false);
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return false;
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case exprstatetype::expect_rhs_expression:
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/* can always begin non-toplevel expression with '(' */
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return true;
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@ -301,6 +337,53 @@ namespace xo {
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case exprstatetype::expect_symbol:
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return false;
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case exprstatetype::expr_progress:
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/* todo: will parse as function call */
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return false;
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case exprstatetype::invalid:
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case exprstatetype::n_exprstatetype:
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/* unreachable */
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assert(false);
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return false;
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}
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return false;
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}
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bool
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exprstate::admits_rightparen() const {
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switch (exs_type_) {
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case exprstatetype::expect_toplevel_expression_sequence:
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case exprstatetype::def_0:
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case exprstatetype::def_1:
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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return false;
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case exprstatetype::lparen_0:
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/* unreachable -- will have pushed expect_rhs_expression */
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assert(false);
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return false;
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case exprstatetype::lparen_1:
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return true;
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case exprstatetype::expect_rhs_expression:
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return false;
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case exprstatetype::expect_type:
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return false;
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case exprstatetype::expect_symbol:
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return false;
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case exprstatetype::expr_progress:
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/* satisfies expression form */
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return true;
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case exprstatetype::invalid:
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case exprstatetype::n_exprstatetype:
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/* unreachable */
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@ -310,7 +393,6 @@ namespace xo {
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return false;
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}
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#endif
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void
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exprstate::on_def(exprstatestack * p_stack) {
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@ -375,10 +457,22 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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/* unreachable */
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assert(false);
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return;
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case exprstatetype::lparen_0:
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/* todo: variable reference */
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assert(false);
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break;
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case exprstatetype::lparen_1:
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/* unreachable */
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assert(false);
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break;
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case exprstatetype::expect_rhs_expression:
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{
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/* various possibilities when looking for rhs expression:
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@ -468,6 +562,8 @@ namespace xo {
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exprstatestack * /*p_stack*/,
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rp<Expression> * /*p_emit_expr*/)
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{
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/* returning type description to somethign that wants it */
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switch (this->exs_type_) {
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case exprstatetype::expect_toplevel_expression_sequence:
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case exprstatetype::def_0:
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@ -487,10 +583,16 @@ namespace xo {
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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/* NOT IMPLEMENTED */
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assert(false);
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return;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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assert(false);
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return;
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case exprstatetype::expect_rhs_expression:
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case exprstatetype::expect_type:
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case exprstatetype::expect_symbol:
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@ -557,6 +659,30 @@ namespace xo {
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p_stack->pop_exprstate(); /* NOT KOSHER. invalidates *this */
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p_stack->top_exprstate().on_expr(expr,
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p_stack,
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p_emit_expr);
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/* control here on input like:
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* (1.234;
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*
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* a. '(' sets up stack [lparen_0:expect_rhs_expression]
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* (see exprstate::on_leftparen())
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* b. 1.234 pushes (in case operators) [lparen_0:expect_rhs_expression:expr_progress]
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* (see exprstate::on_f64())
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* c. semicolon completes expr_progress [lparen_0:expect_rhs_expression]
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* deliver expresssion to expect_rhs_expression.on_expr()
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* (see exprstate::on_expr())
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* d. expr_rhs_expression forwards expression to [lparen_0]
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* e. lparen_0 advances to [lparen_1]
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* f. now deliver semicolon; [lparen_1] rejects
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*/
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p_stack->top_exprstate().on_semicolon(p_stack, p_emit_expr);
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} else if (this->exs_type_ == exprstatetype::def_5) {
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rp<Expression> expr = this->def_expr_;
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p_stack->pop_exprstate(); /* NOT KOSHER. invalidates *this */
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p_stack->top_exprstate().on_expr(expr,
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p_stack,
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p_emit_expr);
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@ -590,25 +716,15 @@ namespace xo {
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}
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}
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#ifdef OBSOLETE
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/**
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consider input:
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x := y(foo())
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Is that an assignment x:=y followed by function call (foo()) ?
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Or assignment with rhs calling a function y() with argument foo()
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policy: forbid parenthesis as beginning of a toplevel expression
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**/
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void
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exprstate::on_leftparen(exprstatestack * p_stack,
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rp<Expression> * p_emit_expr)
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rp<Expression> * /*p_emit_expr*/)
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{
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constexpr bool c_debug_flag = true;
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scope log(XO_DEBUG(c_debug_flag));
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constexpr const char * self_name = "exprstate::on_leftparen";
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if (!this->admits_leftparen())
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{
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throw std::runtime_error(tostr(self_name,
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@ -617,13 +733,64 @@ namespace xo {
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}
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if (this->exs_type_ == exprstatetype::expect_rhs_expression) {
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/* push lparen_0 to remember to look for subsequent rightparen */
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p_stack->push_exprstate(exprstatetype::lparen_0);
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p_stack->push_exprstate(exprstatetype::expect_rhs_expression);
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/* push lparen_0 to remember to look for subsequent rightparen. */
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p_stack->push_exprstate(exprstate::lparen_0());
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p_stack->push_exprstate(exprstate::expect_rhs_expression());
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}
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}
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void
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exprstate::on_rightparen(exprstatestack * p_stack,
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rp<Expression> * p_emit_expr)
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{
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constexpr bool c_debug_flag = true;
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scope log(XO_DEBUG(c_debug_flag));
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constexpr const char * self_name = "exprstate::on_rightparen";
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if (!this->admits_rightparen())
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{
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throw std::runtime_error(tostr(self_name,
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": unexpected rightparen ')' for parsing state",
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xtag("state", *this)));
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}
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if (this->exs_type_ == exprstatetype::expr_progress) {
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/* stack may be something like:
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*
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* lparen_0
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* expect_rhs_expression
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* expr_progress
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* <-- rightparen
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*
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* 1. rightparen completes expression-in-progress
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* 2. rightparen must then match innermost waiting lparen_0
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*/
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/* right paren confirms stack expression */
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rp<Expression> expr = this->gen_expr_;
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p_stack->pop_exprstate(); /* NOT KOSHER. invalidates *this */
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if (p_stack->empty()) {
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throw std::runtime_error(tostr(self_name,
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": expected non-empty parsing stack"));
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}
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log && log(xtag("stack", *p_stack));
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p_stack->top_exprstate().on_expr(expr, p_stack, p_emit_expr);
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/* now deliver rightparen */
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p_stack->top_exprstate().on_rightparen(p_stack, p_emit_expr);
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} else if (this->exs_type_ == exprstatetype::lparen_1) {
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rp<Expression> expr = this->gen_expr_;
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p_stack->pop_exprstate(); /* NOT KOSHER. invalidates *this */
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p_stack->top_exprstate().on_expr(expr, p_stack, p_emit_expr);
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}
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}
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#endif
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void
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exprstate::on_f64(const token_type & tk,
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@ -643,6 +810,10 @@ namespace xo {
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}
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if (this->exs_type_ == exprstatetype::expect_rhs_expression) {
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/* e.g.
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* def pi = 3.14159265;
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* \---tk---/
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*/
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p_stack->push_exprstate
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(exprstate::make_expr_progress
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(Constant<double>::make(tk.f64_value())));
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@ -684,8 +855,13 @@ namespace xo {
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return;
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case tokentype::tk_leftparen:
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this->on_leftparen(p_stack, p_emit_expr);
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return;
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case tokentype::tk_rightparen:
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this->on_rightparen(p_stack, p_emit_expr);
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return;
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case tokentype::tk_leftbracket:
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case tokentype::tk_rightbracket:
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case tokentype::tk_leftbrace:
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@ -772,7 +948,7 @@ namespace xo {
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* Need to be able to locate variable by type
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* 2. if ir_type is an expression, adopt as rhs
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*/
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rp<Expression> rhs_value = expr.get();
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rp<Expression> rhs_value = expr.promote();
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if (this->cvt_expr_)
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this->cvt_expr_->assign_arg(rhs_value);
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@ -781,11 +957,25 @@ namespace xo {
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rp<Expression> def_expr = this->def_expr_;
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p_stack->pop_exprstate(); /* NOT KOSHER. invalidates *this */
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this->exs_type_ = exprstatetype::def_5;
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return;
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}
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p_stack->top_exprstate().on_expr(def_expr,
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p_stack,
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p_emit_expr);
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case exprstatetype::def_5:
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assert(false);
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return;
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case exprstatetype::lparen_0: {
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this->exs_type_ = exprstatetype::lparen_1; /* wants on_rightparen */
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p_stack->push_exprstate(exprstate::make_expr_progress(expr.promote()));
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return;
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}
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case exprstatetype::lparen_1: {
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this->gen_expr_ = expr.promote();
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/* expect immediate incoming call, this time to on_rightparen() */
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return;
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}
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@ -846,6 +1036,13 @@ namespace xo {
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case exprstatetype::def_2:
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case exprstatetype::def_3:
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case exprstatetype::def_4:
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case exprstatetype::def_5:
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/* NOT IMPLEMENTED */
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assert(false);
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return;
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case exprstatetype::lparen_0:
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case exprstatetype::lparen_1:
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/* NOT IMPLEMENTED */
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assert(false);
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return;
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