dawn-cmake/docs/compound_statements.md

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# Compound Statements
Compound statements are statements that can hold other statements.
This document maps the WGSL compound statements to their semantic tree representations.
## if statement
WGSL:
```
if (condition_a) {
statement_a;
} else if (condition_b) {
statement_b;
} else {
statement_c;
}
```
Semantic tree:
```
sem::IfStatement {
condition_a
sem::BlockStatement {
statement_a
}
sem::ElseStatement {
condition_b
sem::BlockStatement {
statement_b
}
}
sem::ElseStatement {
sem::BlockStatement {
statement_c
}
}
}
```
## for loop
WGSL:
```
for (initializer; condition; continuing) {
statement;
}
```
Semantic tree:
```
sem::ForLoopStatement {
sem::Statement initializer
sem::Expression condition
sem::Statement continuing
sem::LoopBlockStatement {
sem::Statement statement
}
}
```
## loop
WGSL:
```
loop (condition) {
statement_a;
continuing {
statement_b;
}
}
```
Semantic tree:
```
sem::LoopStatement {
sem::Expression condition
sem::LoopBlockStatement {
sem::Statement statement_a
sem::LoopContinuingBlockStatement {
sem::Statement statement_b
}
}
}
```
## switch statement
WGSL:
```
switch (condition) {
case literal_a, literal_b: {
statement_a;
}
default {
statement_b;
}
}
```
Semantic tree:
```
sem::SwitchStatement {
sem::Expression condition
sem::SwitchCaseBlockStatement {
sem::Statement statement_a
}
sem::SwitchCaseBlockStatement {
sem::Statement statement_b
}
}
```