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Encapsulate into FlowControl type.

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This commit is contained in:
Stephen Chung
2022-12-23 14:26:06 +08:00
parent 80ccd75514
commit cb09393dba
6 changed files with 158 additions and 133 deletions
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72
src/ast/stmt.rs
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@@ -292,18 +292,6 @@ pub struct SwitchCasesCollection {
pub def_case: Option<usize>,
}
/// _(internals)_ A `try-catch` block.
/// Exported under the `internals` feature only.
#[derive(Debug, Clone, Hash)]
pub struct TryCatchBlock {
/// `try` block.
pub try_block: StmtBlock,
/// `catch` variable, if any.
pub catch_var: Ident,
/// `catch` block.
pub catch_block: StmtBlock,
}
/// Number of items to keep inline for [`StmtBlockContainer`].
#[cfg(not(feature = "no_std"))]
const STMT_BLOCK_INLINE_SIZE: usize = 8;
@@ -532,6 +520,22 @@ impl Extend<Stmt> for StmtBlock {
}
}
/// _(internals)_ A flow control block containing:
/// * an expression,
/// * a statements body
/// * an alternate statements body
///
/// Exported under the `internals` feature only.
#[derive(Debug, Clone, Hash)]
pub struct FlowControl {
/// Flow control expression.
pub expr: Expr,
/// Main body.
pub body: StmtBlock,
/// Branch body.
pub branch: StmtBlock,
}
/// _(internals)_ A statement.
/// Exported under the `internals` feature only.
#[derive(Debug, Clone, Hash)]
@@ -540,7 +544,7 @@ pub enum Stmt {
/// No-op.
Noop(Position),
/// `if` expr `{` stmt `}` `else` `{` stmt `}`
If(Box<(Expr, StmtBlock, StmtBlock)>, Position),
If(Box<FlowControl>, Position),
/// `switch` expr `{` literal or range or _ `if` condition `=>` stmt `,` ... `}`
///
/// ### Data Structure
@@ -552,16 +556,16 @@ pub enum Stmt {
/// `while` expr `{` stmt `}` | `loop` `{` stmt `}`
///
/// If the guard expression is [`UNIT`][Expr::Unit], then it is a `loop` statement.
While(Box<(Expr, StmtBlock)>, Position),
While(Box<FlowControl>, Position),
/// `do` `{` stmt `}` `while`|`until` expr
///
/// ### Flags
///
/// * [`NONE`][ASTFlags::NONE] = `while`
/// * [`NEGATED`][ASTFlags::NEGATED] = `until`
Do(Box<(Expr, StmtBlock)>, ASTFlags, Position),
Do(Box<FlowControl>, ASTFlags, Position),
/// `for` `(` id `,` counter `)` `in` expr `{` stmt `}`
For(Box<(Ident, Ident, Expr, StmtBlock)>, Position),
For(Box<(Ident, Ident, FlowControl)>, Position),
/// \[`export`\] `let`|`const` id `=` expr
///
/// ### Flags
@@ -579,7 +583,7 @@ pub enum Stmt {
/// `{` stmt`;` ... `}`
Block(Box<StmtBlock>),
/// `try` `{` stmt; ... `}` `catch` `(` var `)` `{` stmt; ... `}`
TryCatch(Box<TryCatchBlock>, Position),
TryCatch(Box<FlowControl>, Position),
/// [expression][Expr]
Expr(Box<Expr>),
/// `continue`/`break` expr
@@ -815,7 +819,9 @@ impl Stmt {
Self::Noop(..) => true,
Self::Expr(expr) => expr.is_pure(),
Self::If(x, ..) => {
x.0.is_pure() && x.1.iter().all(Self::is_pure) && x.2.iter().all(Self::is_pure)
x.expr.is_pure()
&& x.body.iter().all(Self::is_pure)
&& x.branch.iter().all(Self::is_pure)
}
Self::Switch(x, ..) => {
let (expr, sw) = &**x;
@@ -833,10 +839,10 @@ impl Stmt {
}
// Loops that exit can be pure because it can never be infinite.
Self::While(x, ..) if matches!(x.0, Expr::BoolConstant(false, ..)) => true,
Self::Do(x, options, ..) if matches!(x.0, Expr::BoolConstant(..)) => match x.0 {
Self::While(x, ..) if matches!(x.expr, Expr::BoolConstant(false, ..)) => true,
Self::Do(x, options, ..) if matches!(x.expr, Expr::BoolConstant(..)) => match x.expr {
Expr::BoolConstant(cond, ..) if cond == options.contains(ASTFlags::NEGATED) => {
x.1.iter().all(Self::is_pure)
x.body.iter().all(Self::is_pure)
}
_ => false,
},
@@ -846,13 +852,15 @@ impl Stmt {
// For loops can be pure because if the iterable is pure, it is finite,
// so infinite loops can never occur.
Self::For(x, ..) => x.2.is_pure() && x.3.iter().all(Self::is_pure),
Self::For(x, ..) => x.2.expr.is_pure() && x.2.body.iter().all(Self::is_pure),
Self::Var(..) | Self::Assignment(..) | Self::FnCall(..) => false,
Self::Block(block, ..) => block.iter().all(Self::is_pure),
Self::BreakLoop(..) | Self::Return(..) => false,
Self::TryCatch(x, ..) => {
x.try_block.iter().all(Self::is_pure) && x.catch_block.iter().all(Self::is_pure)
x.expr.is_pure()
&& x.body.iter().all(Self::is_pure)
&& x.branch.iter().all(Self::is_pure)
}
#[cfg(not(feature = "no_module"))]
@@ -947,15 +955,15 @@ impl Stmt {
}
}
Self::If(x, ..) => {
if !x.0.walk(path, on_node) {
if !x.expr.walk(path, on_node) {
return false;
}
for s in &x.1 {
for s in &x.body {
if !s.walk(path, on_node) {
return false;
}
}
for s in &x.2 {
for s in &x.branch {
if !s.walk(path, on_node) {
return false;
}
@@ -996,20 +1004,20 @@ impl Stmt {
}
}
Self::While(x, ..) | Self::Do(x, ..) => {
if !x.0.walk(path, on_node) {
if !x.expr.walk(path, on_node) {
return false;
}
for s in x.1.statements() {
for s in x.body.statements() {
if !s.walk(path, on_node) {
return false;
}
}
}
Self::For(x, ..) => {
if !x.2.walk(path, on_node) {
if !x.2.expr.walk(path, on_node) {
return false;
}
for s in &x.3 {
for s in &x.2.body {
if !s.walk(path, on_node) {
return false;
}
@@ -1038,12 +1046,12 @@ impl Stmt {
}
}
Self::TryCatch(x, ..) => {
for s in &x.try_block {
for s in &x.body {
if !s.walk(path, on_node) {
return false;
}
}
for s in &x.catch_block {
for s in &x.branch {
if !s.walk(path, on_node) {
return false;
}