eldridge.cam
Actually just three programming languages in a trenchcoat
1use super::*;
2use crate::{Parser, Spanned};
3use trilogy_scanner::TokenType;
4
5#[derive(Clone, Debug, Spanned)]
6pub enum Statement {
7 Let(Box<LetStatement>),
8 Assignment(Box<AssignmentStatement>),
9 FunctionAssignment(Box<FunctionAssignment>),
10 If(Box<IfElseExpression>),
11 Match(Box<MatchExpression>),
12 While(Box<WhileStatement>),
13 For(Box<ForStatement>),
14 Defer(Box<DeferStatement>),
15 Using(Box<UsingStatement>),
16 Assert(Box<AssertStatement>),
17 Expression(Box<Expression>),
18 Block(Box<Block>),
19}
20
21impl Statement {
22 pub(crate) fn parse(parser: &mut Parser) -> SyntaxResult<Self> {
23 let token = parser.peek();
24 use TokenType::*;
25 match token.token_type {
26 KwLet => Ok(Self::Let(Box::new(LetStatement::parse(parser)?))),
27 KwIf => {
28 let expr = IfElseExpression::parse_statement(parser)?;
29 Ok(Self::If(Box::new(expr)))
30 }
31 KwMatch => Ok(Self::Match(Box::new(MatchExpression::parse(parser)?))),
32 KwWhile => Ok(Self::While(Box::new(WhileStatement::parse(parser)?))),
33 KwFor => Ok(Self::For(Box::new(ForStatement::parse(parser)?))),
34 KwDefer => Ok(Self::Defer(Box::new(DeferStatement::parse(parser)?))),
35 KwAssert => Ok(Self::Assert(Box::new(AssertStatement::parse(parser)?))),
36 OBrace => Ok(Self::Block(Box::new(Block::parse(parser)?))),
37 KwUsing => Ok(Self::Using(Box::new(UsingStatement::parse(parser, None)?))),
38 KwDo => {
39 let head = DoHead::parse(parser)?;
40 if parser.check(KwUsing).is_ok() {
41 Ok(Self::Using(Box::new(UsingStatement::parse(
42 parser,
43 Some(head),
44 )?)))
45 } else {
46 let procedure = DoExpression::parse_with_head(parser, head)?;
47 let expression = Expression::Do(Box::new(procedure));
48 Ok(Self::Expression(Box::new(expression)))
49 }
50 }
51 _ => {
52 let expression = Expression::parse(parser)?;
53 if parser.check(IdentifierEq).is_ok() {
54 if !expression.is_lvalue() {
55 parser.error(SyntaxError::new(
56 expression.span(),
57 "cannot assign to an expression that is not a valid assignment target",
58 ));
59 }
60 Ok(Self::FunctionAssignment(Box::new(
61 FunctionAssignment::parse(parser, expression)?,
62 )))
63 } else if parser
64 .check(AssignmentStatement::ASSIGNMENT_OPERATOR)
65 .is_ok()
66 {
67 if !expression.is_lvalue() {
68 parser.error(SyntaxError::new(
69 expression.span(),
70 "cannot assign to an expression that is not a valid assignment target",
71 ));
72 }
73 Ok(Self::Assignment(Box::new(AssignmentStatement::parse(
74 parser, expression,
75 )?)))
76 } else {
77 Ok(Self::Expression(Box::new(expression)))
78 }
79 }
80 }
81 }
82}