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Diffstat (limited to 'src/syntax/ast.rs')
| -rw-r--r-- | src/syntax/ast.rs | 988 |
1 files changed, 988 insertions, 0 deletions
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs new file mode 100644 index 00000000..288c749a --- /dev/null +++ b/src/syntax/ast.rs @@ -0,0 +1,988 @@ +//! A typed layer over the red-green tree. + +use std::ops::Deref; + +use super::{Green, GreenData, NodeKind, RedNode, RedRef, Span}; +use crate::geom::{AngularUnit, LengthUnit}; +use crate::util::EcoString; + +/// A typed AST node. +pub trait TypedNode: Sized { + /// Convert from a red node to a typed node. + fn from_red(value: RedRef) -> Option<Self>; + + /// A reference to the underlying red node. + fn as_red(&self) -> RedRef<'_>; + + /// The source code location. + fn span(&self) -> Span { + self.as_red().span() + } +} + +macro_rules! node { + ($(#[$attr:meta])* $name:ident) => { + node!{$(#[$attr])* $name: $name} + }; + ($(#[$attr:meta])* $name:ident: $variant:ident) => { + node!{$(#[$attr])* $name: NodeKind::$variant} + }; + ($(#[$attr:meta])* $name:ident: $($variant:pat)|*) => { + #[derive(Debug, Clone, PartialEq)] + #[repr(transparent)] + $(#[$attr])* + pub struct $name(RedNode); + + impl TypedNode for $name { + fn from_red(node: RedRef) -> Option<Self> { + if matches!(node.kind(), $($variant)|*) { + Some(Self(node.own())) + } else { + None + } + } + + fn as_red(&self) -> RedRef<'_> { + self.0.as_ref() + } + } + }; +} + +node! { + /// The syntactical root capable of representing a full parsed document. + Markup +} + +impl Markup { + /// The markup nodes. + pub fn nodes(&self) -> impl Iterator<Item = MarkupNode> + '_ { + self.0.children().filter_map(|node| match node.kind() { + NodeKind::Space(_) => Some(MarkupNode::Space), + NodeKind::Linebreak => Some(MarkupNode::Linebreak), + NodeKind::Parbreak => Some(MarkupNode::Parbreak), + NodeKind::Strong => Some(MarkupNode::Strong), + NodeKind::Emph => Some(MarkupNode::Emph), + NodeKind::Text(s) => Some(MarkupNode::Text(s.clone())), + NodeKind::UnicodeEscape(c) => Some(MarkupNode::Text((*c).into())), + NodeKind::EnDash => Some(MarkupNode::Text("\u{2013}".into())), + NodeKind::EmDash => Some(MarkupNode::Text("\u{2014}".into())), + NodeKind::NonBreakingSpace => Some(MarkupNode::Text("\u{00A0}".into())), + NodeKind::Math(math) => Some(MarkupNode::Math(math.as_ref().clone())), + NodeKind::Raw(raw) => Some(MarkupNode::Raw(raw.as_ref().clone())), + NodeKind::Heading => node.cast().map(MarkupNode::Heading), + NodeKind::List => node.cast().map(MarkupNode::List), + NodeKind::Enum => node.cast().map(MarkupNode::Enum), + _ => node.cast().map(MarkupNode::Expr), + }) + } +} + +/// A single piece of markup. +#[derive(Debug, Clone, PartialEq)] +pub enum MarkupNode { + /// Whitespace containing less than two newlines. + Space, + /// A forced line break: `\`. + Linebreak, + /// A paragraph break: Two or more newlines. + Parbreak, + /// Strong text was enabled / disabled: `*`. + Strong, + /// Emphasized text was enabled / disabled: `_`. + Emph, + /// Plain text. + Text(EcoString), + /// A raw block with optional syntax highlighting: `` `...` ``. + Raw(RawNode), + /// A math formula: `$a^2 = b^2 + c^2$`. + Math(MathNode), + /// A section heading: `= Introduction`. + Heading(HeadingNode), + /// An item in an unordered list: `- ...`. + List(ListNode), + /// An item in an enumeration (ordered list): `1. ...`. + Enum(EnumNode), + /// An expression. + Expr(Expr), +} + +/// A raw block with optional syntax highlighting: `` `...` ``. +#[derive(Debug, Clone, PartialEq)] +pub struct RawNode { + /// An optional identifier specifying the language to syntax-highlight in. + pub lang: Option<EcoString>, + /// The raw text, determined as the raw string between the backticks trimmed + /// according to the above rules. + pub text: EcoString, + /// Whether the element is block-level, that is, it has 3+ backticks + /// and contains at least one newline. + pub block: bool, +} + +/// A math formula: `$a^2 + b^2 = c^2$`. +#[derive(Debug, Clone, PartialEq)] +pub struct MathNode { + /// The formula between the dollars / brackets. + pub formula: EcoString, + /// Whether the formula is display-level, that is, it is surrounded by + /// `$[..]$`. + pub display: bool, +} + +node! { + /// A section heading: `= Introduction`. + HeadingNode: Heading +} + +impl HeadingNode { + /// The contents of the heading. + pub fn body(&self) -> Markup { + self.0.cast_first_child().expect("heading is missing markup body") + } + + /// The section depth (numer of equals signs). + pub fn level(&self) -> usize { + self.0.children().filter(|n| n.kind() == &NodeKind::Eq).count() + } +} + +node! { + /// An item in an unordered list: `- ...`. + ListNode: List +} + +impl ListNode { + /// The contents of the list item. + pub fn body(&self) -> Markup { + self.0.cast_first_child().expect("list node is missing body") + } +} + +node! { + /// An item in an enumeration (ordered list): `1. ...`. + EnumNode: Enum +} + +impl EnumNode { + /// The contents of the list item. + pub fn body(&self) -> Markup { + self.0.cast_first_child().expect("enum node is missing body") + } + + /// The number, if any. + pub fn number(&self) -> Option<usize> { + self.0 + .children() + .find_map(|node| match node.kind() { + NodeKind::EnumNumbering(num) => Some(num.clone()), + _ => None, + }) + .expect("enum node is missing number") + } +} + +/// An expression. +#[derive(Debug, Clone, PartialEq)] +pub enum Expr { + /// A literal: `1`, `true`, ... + Lit(Lit), + /// An identifier: `left`. + Ident(Ident), + /// An array expression: `(1, "hi", 12cm)`. + Array(ArrayExpr), + /// A dictionary expression: `(thickness: 3pt, pattern: dashed)`. + Dict(DictExpr), + /// A template expression: `[*Hi* there!]`. + Template(TemplateExpr), + /// A grouped expression: `(1 + 2)`. + Group(GroupExpr), + /// A block expression: `{ let x = 1; x + 2 }`. + Block(BlockExpr), + /// A unary operation: `-x`. + Unary(UnaryExpr), + /// A binary operation: `a + b`. + Binary(BinaryExpr), + /// An invocation of a function: `f(x, y)`. + Call(CallExpr), + /// A closure expression: `(x, y) => z`. + Closure(ClosureExpr), + /// A with expression: `f with (x, y: 1)`. + With(WithExpr), + /// A let expression: `let x = 1`. + Let(LetExpr), + /// An if-else expression: `if x { y } else { z }`. + If(IfExpr), + /// A while loop expression: `while x { y }`. + While(WhileExpr), + /// A for loop expression: `for x in y { z }`. + For(ForExpr), + /// An import expression: `import a, b, c from "utils.typ"`. + Import(ImportExpr), + /// An include expression: `include "chapter1.typ"`. + Include(IncludeExpr), +} + +impl TypedNode for Expr { + fn from_red(node: RedRef) -> Option<Self> { + match node.kind() { + NodeKind::Ident(_) => node.cast().map(Self::Ident), + NodeKind::Array => node.cast().map(Self::Array), + NodeKind::Dict => node.cast().map(Self::Dict), + NodeKind::Template => node.cast().map(Self::Template), + NodeKind::Group => node.cast().map(Self::Group), + NodeKind::Block => node.cast().map(Self::Block), + NodeKind::Unary => node.cast().map(Self::Unary), + NodeKind::Binary => node.cast().map(Self::Binary), + NodeKind::Call => node.cast().map(Self::Call), + NodeKind::Closure => node.cast().map(Self::Closure), + NodeKind::WithExpr => node.cast().map(Self::With), + NodeKind::LetExpr => node.cast().map(Self::Let), + NodeKind::IfExpr => node.cast().map(Self::If), + NodeKind::WhileExpr => node.cast().map(Self::While), + NodeKind::ForExpr => node.cast().map(Self::For), + NodeKind::ImportExpr => node.cast().map(Self::Import), + NodeKind::IncludeExpr => node.cast().map(Self::Include), + _ => node.cast().map(Self::Lit), + } + } + + fn as_red(&self) -> RedRef<'_> { + match self { + Self::Lit(v) => v.as_red(), + Self::Ident(v) => v.as_red(), + Self::Array(v) => v.as_red(), + Self::Dict(v) => v.as_red(), + Self::Template(v) => v.as_red(), + Self::Group(v) => v.as_red(), + Self::Block(v) => v.as_red(), + Self::Unary(v) => v.as_red(), + Self::Binary(v) => v.as_red(), + Self::Call(v) => v.as_red(), + Self::Closure(v) => v.as_red(), + Self::With(v) => v.as_red(), + Self::Let(v) => v.as_red(), + Self::If(v) => v.as_red(), + Self::While(v) => v.as_red(), + Self::For(v) => v.as_red(), + Self::Import(v) => v.as_red(), + Self::Include(v) => v.as_red(), + } + } +} + +impl Expr { + /// Whether the expression can be shortened in markup with a hashtag. + pub fn has_short_form(&self) -> bool { + matches!(self, + Self::Ident(_) + | Self::Call(_) + | Self::Let(_) + | Self::If(_) + | Self::While(_) + | Self::For(_) + | Self::Import(_) + | Self::Include(_) + ) + } +} + +node! { + /// A literal: `1`, `true`, ... + Lit: NodeKind::None + | NodeKind::Auto + | NodeKind::Bool(_) + | NodeKind::Int(_) + | NodeKind::Float(_) + | NodeKind::Length(_, _) + | NodeKind::Angle(_, _) + | NodeKind::Percentage(_) + | NodeKind::Fraction(_) + | NodeKind::Str(_) +} + +impl Lit { + /// The kind of literal. + pub fn kind(&self) -> LitKind { + match *self.0.kind() { + NodeKind::None => LitKind::None, + NodeKind::Auto => LitKind::Auto, + NodeKind::Bool(v) => LitKind::Bool(v), + NodeKind::Int(v) => LitKind::Int(v), + NodeKind::Float(v) => LitKind::Float(v), + NodeKind::Length(v, unit) => LitKind::Length(v, unit), + NodeKind::Angle(v, unit) => LitKind::Angle(v, unit), + NodeKind::Percentage(v) => LitKind::Percent(v), + NodeKind::Fraction(v) => LitKind::Fractional(v), + NodeKind::Str(ref v) => LitKind::Str(v.clone()), + _ => panic!("literal is of wrong kind"), + } + } +} + +/// The kind of a literal. +#[derive(Debug, Clone, PartialEq)] +pub enum LitKind { + /// The none literal: `none`. + None, + /// The auto literal: `auto`. + Auto, + /// A boolean literal: `true`, `false`. + Bool(bool), + /// An integer literal: `120`. + Int(i64), + /// A floating-point literal: `1.2`, `10e-4`. + Float(f64), + /// A length literal: `12pt`, `3cm`. + Length(f64, LengthUnit), + /// An angle literal: `1.5rad`, `90deg`. + Angle(f64, AngularUnit), + /// A percent literal: `50%`. + /// + /// _Note_: `50%` is stored as `50.0` here, but as `0.5` in the + /// corresponding [value](crate::geom::Relative). + Percent(f64), + /// A fraction unit literal: `1fr`. + Fractional(f64), + /// A string literal: `"hello!"`. + Str(EcoString), +} + +node! { + /// An array expression: `(1, "hi", 12cm)`. + ArrayExpr: Array +} + +impl ArrayExpr { + /// The array items. + pub fn items(&self) -> impl Iterator<Item = Expr> + '_ { + self.0.children().filter_map(RedRef::cast) + } +} + +node! { + /// A dictionary expression: `(thickness: 3pt, pattern: dashed)`. + DictExpr: Dict +} + +impl DictExpr { + /// The named dictionary items. + pub fn items(&self) -> impl Iterator<Item = Named> + '_ { + self.0.children().filter_map(RedRef::cast) + } +} + +node! { + /// A pair of a name and an expression: `pattern: dashed`. + Named +} + +impl Named { + /// The name: `pattern`. + pub fn name(&self) -> Ident { + self.0.cast_first_child().expect("named pair is missing name") + } + + /// The right-hand side of the pair: `dashed`. + pub fn expr(&self) -> Expr { + self.0.cast_last_child().expect("named pair is missing expression") + } +} + +node! { + /// A template expression: `[*Hi* there!]`. + TemplateExpr: Template +} + +impl TemplateExpr { + /// The contents of the template. + pub fn body(&self) -> Markup { + self.0.cast_first_child().expect("template is missing body") + } +} + +node! { + /// A grouped expression: `(1 + 2)`. + GroupExpr: Group +} + +impl GroupExpr { + /// The wrapped expression. + pub fn expr(&self) -> Expr { + self.0.cast_first_child().expect("group is missing expression") + } +} + +node! { + /// A block expression: `{ let x = 1; x + 2 }`. + BlockExpr: Block +} + +impl BlockExpr { + /// The list of expressions contained in the block. + pub fn exprs(&self) -> impl Iterator<Item = Expr> + '_ { + self.0.children().filter_map(RedRef::cast) + } +} + +node! { + /// A unary operation: `-x`. + UnaryExpr: Unary +} + +impl UnaryExpr { + /// The operator: `-`. + pub fn op(&self) -> UnOp { + self.0 + .children() + .find_map(|node| UnOp::from_token(node.kind())) + .expect("unary expression is missing operator") + } + + /// The expression to operator on: `x`. + pub fn expr(&self) -> Expr { + self.0.cast_last_child().expect("unary expression is missing child") + } +} + +/// A unary operator. +#[derive(Debug, Copy, Clone, Eq, PartialEq)] +pub enum UnOp { + /// The plus operator: `+`. + Pos, + /// The negation operator: `-`. + Neg, + /// The boolean `not`. + Not, +} + +impl UnOp { + /// Try to convert the token into a unary operation. + pub fn from_token(token: &NodeKind) -> Option<Self> { + Some(match token { + NodeKind::Plus => Self::Pos, + NodeKind::Minus => Self::Neg, + NodeKind::Not => Self::Not, + _ => return None, + }) + } + + /// The precedence of this operator. + pub fn precedence(self) -> usize { + match self { + Self::Pos | Self::Neg => 7, + Self::Not => 4, + } + } + + /// The string representation of this operation. + pub fn as_str(self) -> &'static str { + match self { + Self::Pos => "+", + Self::Neg => "-", + Self::Not => "not", + } + } +} + +node! { + /// A binary operation: `a + b`. + BinaryExpr: Binary +} + +impl BinaryExpr { + /// The binary operator: `+`. + pub fn op(&self) -> BinOp { + self.0 + .children() + .find_map(|node| BinOp::from_token(node.kind())) + .expect("binary expression is missing operator") + } + + /// The left-hand side of the operation: `a`. + pub fn lhs(&self) -> Expr { + self.0 + .cast_first_child() + .expect("binary expression is missing left-hand side") + } + + /// The right-hand side of the operation: `b`. + pub fn rhs(&self) -> Expr { + self.0 + .cast_last_child() + .expect("binary expression is missing right-hand side") + } +} + +/// A binary operator. +#[derive(Debug, Copy, Clone, Eq, PartialEq)] +pub enum BinOp { + /// The addition operator: `+`. + Add, + /// The subtraction operator: `-`. + Sub, + /// The multiplication operator: `*`. + Mul, + /// The division operator: `/`. + Div, + /// The short-circuiting boolean `and`. + And, + /// The short-circuiting boolean `or`. + Or, + /// The equality operator: `==`. + Eq, + /// The inequality operator: `!=`. + Neq, + /// The less-than operator: `<`. + Lt, + /// The less-than or equal operator: `<=`. + Leq, + /// The greater-than operator: `>`. + Gt, + /// The greater-than or equal operator: `>=`. + Geq, + /// The assignment operator: `=`. + Assign, + /// The add-assign operator: `+=`. + AddAssign, + /// The subtract-assign oeprator: `-=`. + SubAssign, + /// The multiply-assign operator: `*=`. + MulAssign, + /// The divide-assign operator: `/=`. + DivAssign, +} + +impl BinOp { + /// Try to convert the token into a binary operation. + pub fn from_token(token: &NodeKind) -> Option<Self> { + Some(match token { + NodeKind::Plus => Self::Add, + NodeKind::Minus => Self::Sub, + NodeKind::Star => Self::Mul, + NodeKind::Slash => Self::Div, + NodeKind::And => Self::And, + NodeKind::Or => Self::Or, + NodeKind::EqEq => Self::Eq, + NodeKind::ExclEq => Self::Neq, + NodeKind::Lt => Self::Lt, + NodeKind::LtEq => Self::Leq, + NodeKind::Gt => Self::Gt, + NodeKind::GtEq => Self::Geq, + NodeKind::Eq => Self::Assign, + NodeKind::PlusEq => Self::AddAssign, + NodeKind::HyphEq => Self::SubAssign, + NodeKind::StarEq => Self::MulAssign, + NodeKind::SlashEq => Self::DivAssign, + _ => return None, + }) + } + + /// The precedence of this operator. + pub fn precedence(self) -> usize { + match self { + Self::Mul | Self::Div => 6, + Self::Add | Self::Sub => 5, + Self::Eq | Self::Neq | Self::Lt | Self::Leq | Self::Gt | Self::Geq => 4, + Self::And => 3, + Self::Or => 2, + Self::Assign + | Self::AddAssign + | Self::SubAssign + | Self::MulAssign + | Self::DivAssign => 1, + } + } + + /// The associativity of this operator. + pub fn associativity(self) -> Associativity { + match self { + Self::Add + | Self::Sub + | Self::Mul + | Self::Div + | Self::And + | Self::Or + | Self::Eq + | Self::Neq + | Self::Lt + | Self::Leq + | Self::Gt + | Self::Geq => Associativity::Left, + Self::Assign + | Self::AddAssign + | Self::SubAssign + | Self::MulAssign + | Self::DivAssign => Associativity::Right, + } + } + + /// The string representation of this operation. + pub fn as_str(self) -> &'static str { + match self { + Self::Add => "+", + Self::Sub => "-", + Self::Mul => "*", + Self::Div => "/", + Self::And => "and", + Self::Or => "or", + Self::Eq => "==", + Self::Neq => "!=", + Self::Lt => "<", + Self::Leq => "<=", + Self::Gt => ">", + Self::Geq => ">=", + Self::Assign => "=", + Self::AddAssign => "+=", + Self::SubAssign => "-=", + Self::MulAssign => "*=", + Self::DivAssign => "/=", + } + } +} + +/// The associativity of a binary operator. +#[derive(Debug, Copy, Clone, Eq, PartialEq)] +pub enum Associativity { + /// Left-associative: `a + b + c` is equivalent to `(a + b) + c`. + Left, + /// Right-associative: `a = b = c` is equivalent to `a = (b = c)`. + Right, +} + +node! { + /// An invocation of a function: `foo(...)`. + CallExpr: Call +} + +impl CallExpr { + /// The function to call. + pub fn callee(&self) -> Expr { + self.0.cast_first_child().expect("call is missing callee") + } + + /// The arguments to the function. + pub fn args(&self) -> CallArgs { + self.0.cast_last_child().expect("call is missing argument list") + } +} + +node! { + /// The arguments to a function: `12, draw: false`. + CallArgs +} + +impl CallArgs { + /// The positional and named arguments. + pub fn items(&self) -> impl Iterator<Item = CallArg> + '_ { + self.0.children().filter_map(RedRef::cast) + } +} + +/// An argument to a function call. +#[derive(Debug, Clone, PartialEq)] +pub enum CallArg { + /// A positional argument: `12`. + Pos(Expr), + /// A named argument: `draw: false`. + Named(Named), + /// A spreaded argument: `..things`. + Spread(Expr), +} + +impl TypedNode for CallArg { + fn from_red(node: RedRef) -> Option<Self> { + match node.kind() { + NodeKind::Named => node.cast().map(CallArg::Named), + NodeKind::Spread => node.cast_first_child().map(CallArg::Spread), + _ => node.cast().map(CallArg::Pos), + } + } + + fn as_red(&self) -> RedRef<'_> { + match self { + Self::Pos(v) => v.as_red(), + Self::Named(v) => v.as_red(), + Self::Spread(v) => v.as_red(), + } + } +} + +impl CallArg { + /// The name of this argument. + pub fn span(&self) -> Span { + match self { + Self::Pos(expr) => expr.span(), + Self::Named(named) => named.span(), + Self::Spread(expr) => expr.span(), + } + } +} + +node! { + /// A closure expression: `(x, y) => z`. + ClosureExpr: Closure +} + +impl ClosureExpr { + /// The name of the closure. + /// + /// This only exists if you use the function syntax sugar: `let f(x) = y`. + pub fn name(&self) -> Option<Ident> { + self.0.cast_first_child() + } + + /// The parameter bindings. + pub fn params(&self) -> impl Iterator<Item = ClosureParam> + '_ { + self.0 + .children() + .find(|x| x.kind() == &NodeKind::ClosureParams) + .expect("closure is missing parameter list") + .children() + .filter_map(RedRef::cast) + } + + /// The body of the closure. + pub fn body(&self) -> Expr { + self.0.cast_last_child().expect("closure is missing body") + } +} + +/// A parameter to a closure. +#[derive(Debug, Clone, PartialEq)] +pub enum ClosureParam { + /// A positional parameter: `x`. + Pos(Ident), + /// A named parameter with a default value: `draw: false`. + Named(Named), + /// A parameter sink: `..args`. + Sink(Ident), +} + +impl TypedNode for ClosureParam { + fn from_red(node: RedRef) -> Option<Self> { + match node.kind() { + NodeKind::Ident(_) => node.cast().map(ClosureParam::Pos), + NodeKind::Named => node.cast().map(ClosureParam::Named), + NodeKind::Spread => node.cast_first_child().map(ClosureParam::Sink), + _ => None, + } + } + + fn as_red(&self) -> RedRef<'_> { + match self { + Self::Pos(v) => v.as_red(), + Self::Named(v) => v.as_red(), + Self::Sink(v) => v.as_red(), + } + } +} + +node! { + /// A with expression: `f with (x, y: 1)`. + WithExpr +} + +impl WithExpr { + /// The function to apply the arguments to. + pub fn callee(&self) -> Expr { + self.0.cast_first_child().expect("with expression is missing callee") + } + + /// The arguments to apply to the function. + pub fn args(&self) -> CallArgs { + self.0 + .cast_first_child() + .expect("with expression is missing argument list") + } +} + +node! { + /// A let expression: `let x = 1`. + LetExpr +} + +impl LetExpr { + /// The binding to assign to. + pub fn binding(&self) -> Ident { + match self.0.cast_first_child() { + Some(Expr::Ident(binding)) => binding, + Some(Expr::With(with)) => match with.callee() { + Expr::Ident(binding) => binding, + _ => panic!("let .. with callee must be identifier"), + }, + Some(Expr::Closure(closure)) => { + closure.name().expect("let-bound closure is missing name") + } + _ => panic!("let expression is missing binding"), + } + } + + /// The expression the binding is initialized with. + pub fn init(&self) -> Option<Expr> { + if self.0.cast_first_child::<Ident>().is_some() { + self.0.children().filter_map(RedRef::cast).nth(1) + } else { + // This is a let .. with expression. + self.0.cast_first_child() + } + } +} + +node! { + /// An import expression: `import a, b, c from "utils.typ"`. + ImportExpr +} + +impl ImportExpr { + /// The items to be imported. + pub fn imports(&self) -> Imports { + self.0 + .children() + .find_map(|node| match node.kind() { + NodeKind::Star => Some(Imports::Wildcard), + NodeKind::ImportItems => { + let items = node.children().filter_map(RedRef::cast).collect(); + Some(Imports::Items(items)) + } + _ => None, + }) + .expect("import is missing items") + } + + /// The location of the importable file. + pub fn path(&self) -> Expr { + self.0.cast_last_child().expect("import is missing path") + } +} + +/// The items that ought to be imported from a file. +#[derive(Debug, Clone, PartialEq)] +pub enum Imports { + /// All items in the scope of the file should be imported. + Wildcard, + /// The specified items from the file should be imported. + Items(Vec<Ident>), +} + +node! { + /// An include expression: `include "chapter1.typ"`. + IncludeExpr +} + +impl IncludeExpr { + /// The location of the file to be included. + pub fn path(&self) -> Expr { + self.0.cast_last_child().expect("include is missing path") + } +} + +node! { + /// An if-else expression: `if x { y } else { z }`. + IfExpr +} + +impl IfExpr { + /// The condition which selects the body to evaluate. + pub fn condition(&self) -> Expr { + self.0.cast_first_child().expect("if expression is missing condition") + } + + /// The expression to evaluate if the condition is true. + pub fn if_body(&self) -> Expr { + self.0 + .children() + .filter_map(RedRef::cast) + .nth(1) + .expect("if expression is missing body") + } + + /// The expression to evaluate if the condition is false. + pub fn else_body(&self) -> Option<Expr> { + self.0.children().filter_map(RedRef::cast).nth(2) + } +} + +node! { + /// A while loop expression: `while x { y }`. + WhileExpr +} + +impl WhileExpr { + /// The condition which selects whether to evaluate the body. + pub fn condition(&self) -> Expr { + self.0.cast_first_child().expect("while loop is missing condition") + } + + /// The expression to evaluate while the condition is true. + pub fn body(&self) -> Expr { + self.0.cast_last_child().expect("while loop is missing body") + } +} + +node! { + /// A for loop expression: `for x in y { z }`. + ForExpr +} + +impl ForExpr { + /// The pattern to assign to. + pub fn pattern(&self) -> ForPattern { + self.0.cast_first_child().expect("for loop is missing pattern") + } + + /// The expression to iterate over. + pub fn iter(&self) -> Expr { + self.0.cast_first_child().expect("for loop is missing iterable") + } + + /// The expression to evaluate for each iteration. + pub fn body(&self) -> Expr { + self.0.cast_last_child().expect("for loop is missing body") + } +} + +node! { + /// A for-in loop expression: `for x in y { z }`. + ForPattern +} + +impl ForPattern { + /// The key part of the pattern: index for arrays, name for dictionaries. + pub fn key(&self) -> Option<Ident> { + let mut children = self.0.children().filter_map(RedRef::cast); + let key = children.next(); + if children.next().is_some() { key } else { None } + } + + /// The value part of the pattern. + pub fn value(&self) -> Ident { + self.0.cast_last_child().expect("for loop pattern is missing value") + } +} + +node! { + /// An identifier. + Ident: NodeKind::Ident(_) +} + +impl Ident { + /// Take out the contained [`EcoString`]. + pub fn take(self) -> EcoString { + match self.0.green { + Green::Token(GreenData { kind: NodeKind::Ident(id), .. }) => id, + _ => panic!("identifier is of wrong kind"), + } + } +} + +impl Deref for Ident { + type Target = str; + + fn deref(&self) -> &Self::Target { + match &self.0.green { + Green::Token(GreenData { kind: NodeKind::Ident(id), .. }) => id, + _ => panic!("identifier is of wrong kind"), + } + } +} |