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Instead of using an `if` node that has a list of `else` statements, make each `if` statement have a single optional `else` statement, which may itself be an `if` statement (or just a block statement). This better matches the WGSL grammar (now that we have removed `elseif`), and simplifies various pieces of code that handle these statements. Change-Id: Ie4272f1422224490ac598a03aa8b4dd00ba03010 Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/87940 Kokoro: Kokoro <noreply+kokoro@google.com> Reviewed-by: Antonio Maiorano <amaiorano@google.com> Commit-Queue: James Price <jrprice@google.com>
118 lines
1.7 KiB
Markdown
118 lines
1.7 KiB
Markdown
# Compound Statements
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Compound statements are statements that can hold other statements.
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This document maps the WGSL compound statements to their semantic tree representations.
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## if statement
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WGSL:
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```
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if (condition_a) {
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statement_a;
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} else if (condition_b) {
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statement_b;
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} else {
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statement_c;
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}
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```
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Semantic tree:
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```
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sem::IfStatement {
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condition_a
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sem::BlockStatement {
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statement_a
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}
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sem::IfStatement {
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condition_b
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sem::BlockStatement {
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statement_b
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}
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sem::BlockStatement {
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statement_c
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}
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}
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}
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```
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## for loop
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WGSL:
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```
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for (initializer; condition; continuing) {
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statement;
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}
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```
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Semantic tree:
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```
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sem::ForLoopStatement {
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sem::Statement initializer
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sem::Expression condition
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sem::Statement continuing
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sem::LoopBlockStatement {
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sem::Statement statement
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}
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}
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```
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## loop
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WGSL:
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```
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loop (condition) {
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statement_a;
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continuing {
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statement_b;
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}
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}
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```
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Semantic tree:
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```
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sem::LoopStatement {
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sem::Expression condition
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sem::LoopBlockStatement {
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sem::Statement statement_a
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sem::LoopContinuingBlockStatement {
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sem::Statement statement_b
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}
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}
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}
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```
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## switch statement
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WGSL:
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```
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switch (condition) {
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case literal_a, literal_b: {
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statement_a;
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}
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default {
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statement_b;
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}
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}
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```
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Semantic tree:
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```
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sem::SwitchStatement {
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sem::Expression condition
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sem::CaseStatement {
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sem::BlockStatement {
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sem::Statement statement_a
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}
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}
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sem::CaseStatement {
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sem::BlockStatement {
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sem::Statement statement_b
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}
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}
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}
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```
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