harn_parser/
ast.rs

1use harn_lexer::{Span, StringSegment};
2
3/// A node wrapped with source location information.
4#[derive(Debug, Clone, PartialEq)]
5pub struct Spanned<T> {
6    pub node: T,
7    pub span: Span,
8}
9
10impl<T> Spanned<T> {
11    pub fn new(node: T, span: Span) -> Self {
12        Self { node, span }
13    }
14
15    pub fn dummy(node: T) -> Self {
16        Self {
17            node,
18            span: Span::dummy(),
19        }
20    }
21}
22
23/// A spanned AST node — the primary unit throughout the compiler.
24pub type SNode = Spanned<Node>;
25
26/// Helper to wrap a node with a span.
27pub fn spanned(node: Node, span: Span) -> SNode {
28    SNode::new(node, span)
29}
30
31/// AST nodes for the Harn language.
32#[derive(Debug, Clone, PartialEq)]
33pub enum Node {
34    // Declarations
35    Pipeline {
36        name: String,
37        params: Vec<String>,
38        body: Vec<SNode>,
39        extends: Option<String>,
40    },
41    LetBinding {
42        name: String,
43        type_ann: Option<TypeExpr>,
44        value: Box<SNode>,
45    },
46    VarBinding {
47        name: String,
48        type_ann: Option<TypeExpr>,
49        value: Box<SNode>,
50    },
51    OverrideDecl {
52        name: String,
53        params: Vec<String>,
54        body: Vec<SNode>,
55    },
56    ImportDecl {
57        path: String,
58    },
59    /// Selective import: import { foo, bar } from "module"
60    SelectiveImport {
61        names: Vec<String>,
62        path: String,
63    },
64    EnumDecl {
65        name: String,
66        variants: Vec<EnumVariant>,
67    },
68    StructDecl {
69        name: String,
70        fields: Vec<StructField>,
71    },
72    InterfaceDecl {
73        name: String,
74        methods: Vec<InterfaceMethod>,
75    },
76
77    // Control flow
78    IfElse {
79        condition: Box<SNode>,
80        then_body: Vec<SNode>,
81        else_body: Option<Vec<SNode>>,
82    },
83    ForIn {
84        variable: String,
85        iterable: Box<SNode>,
86        body: Vec<SNode>,
87    },
88    MatchExpr {
89        value: Box<SNode>,
90        arms: Vec<MatchArm>,
91    },
92    WhileLoop {
93        condition: Box<SNode>,
94        body: Vec<SNode>,
95    },
96    Retry {
97        count: Box<SNode>,
98        body: Vec<SNode>,
99    },
100    ReturnStmt {
101        value: Option<Box<SNode>>,
102    },
103    TryCatch {
104        body: Vec<SNode>,
105        error_var: Option<String>,
106        error_type: Option<TypeExpr>,
107        catch_body: Vec<SNode>,
108    },
109    FnDecl {
110        name: String,
111        params: Vec<TypedParam>,
112        return_type: Option<TypeExpr>,
113        body: Vec<SNode>,
114        is_pub: bool,
115    },
116    TypeDecl {
117        name: String,
118        type_expr: TypeExpr,
119    },
120    SpawnExpr {
121        body: Vec<SNode>,
122    },
123    /// Duration literal: 500ms, 5s, 30m, 2h
124    DurationLiteral(u64),
125    /// Range expression: start upto end (exclusive) or start thru end (inclusive)
126    RangeExpr {
127        start: Box<SNode>,
128        end: Box<SNode>,
129        inclusive: bool,
130    },
131    /// Guard clause: guard condition else { body }
132    GuardStmt {
133        condition: Box<SNode>,
134        else_body: Vec<SNode>,
135    },
136    /// Ask expression: ask { system: "...", user: "...", ... }
137    AskExpr {
138        fields: Vec<DictEntry>,
139    },
140    /// Deadline block: deadline DURATION { body }
141    DeadlineBlock {
142        duration: Box<SNode>,
143        body: Vec<SNode>,
144    },
145    /// Yield expression: yields control to host, optionally with a value.
146    YieldExpr {
147        value: Option<Box<SNode>>,
148    },
149    /// Mutex block: mutual exclusion for concurrent access.
150    MutexBlock {
151        body: Vec<SNode>,
152    },
153    /// Break out of a loop.
154    BreakStmt,
155    /// Continue to next loop iteration.
156    ContinueStmt,
157
158    // Concurrency
159    Parallel {
160        count: Box<SNode>,
161        variable: Option<String>,
162        body: Vec<SNode>,
163    },
164    ParallelMap {
165        list: Box<SNode>,
166        variable: String,
167        body: Vec<SNode>,
168    },
169
170    // Expressions
171    FunctionCall {
172        name: String,
173        args: Vec<SNode>,
174    },
175    MethodCall {
176        object: Box<SNode>,
177        method: String,
178        args: Vec<SNode>,
179    },
180    PropertyAccess {
181        object: Box<SNode>,
182        property: String,
183    },
184    SubscriptAccess {
185        object: Box<SNode>,
186        index: Box<SNode>,
187    },
188    BinaryOp {
189        op: String,
190        left: Box<SNode>,
191        right: Box<SNode>,
192    },
193    UnaryOp {
194        op: String,
195        operand: Box<SNode>,
196    },
197    Ternary {
198        condition: Box<SNode>,
199        true_expr: Box<SNode>,
200        false_expr: Box<SNode>,
201    },
202    Assignment {
203        target: Box<SNode>,
204        value: Box<SNode>,
205        /// None = plain `=`, Some("+") = `+=`, etc.
206        op: Option<String>,
207    },
208    ThrowStmt {
209        value: Box<SNode>,
210    },
211
212    /// Enum variant construction: EnumName.Variant(args)
213    EnumConstruct {
214        enum_name: String,
215        variant: String,
216        args: Vec<SNode>,
217    },
218    /// Struct construction: StructName { field: value, ... }
219    StructConstruct {
220        struct_name: String,
221        fields: Vec<DictEntry>,
222    },
223
224    // Literals
225    InterpolatedString(Vec<StringSegment>),
226    StringLiteral(String),
227    IntLiteral(i64),
228    FloatLiteral(f64),
229    BoolLiteral(bool),
230    NilLiteral,
231    Identifier(String),
232    ListLiteral(Vec<SNode>),
233    DictLiteral(Vec<DictEntry>),
234
235    // Blocks
236    Block(Vec<SNode>),
237    Closure {
238        params: Vec<TypedParam>,
239        body: Vec<SNode>,
240    },
241}
242
243#[derive(Debug, Clone, PartialEq)]
244pub struct MatchArm {
245    pub pattern: SNode,
246    pub body: Vec<SNode>,
247}
248
249#[derive(Debug, Clone, PartialEq)]
250pub struct DictEntry {
251    pub key: SNode,
252    pub value: SNode,
253}
254
255/// An enum variant declaration.
256#[derive(Debug, Clone, PartialEq)]
257pub struct EnumVariant {
258    pub name: String,
259    pub fields: Vec<TypedParam>,
260}
261
262/// A struct field declaration.
263#[derive(Debug, Clone, PartialEq)]
264pub struct StructField {
265    pub name: String,
266    pub type_expr: Option<TypeExpr>,
267    pub optional: bool,
268}
269
270/// An interface method signature.
271#[derive(Debug, Clone, PartialEq)]
272pub struct InterfaceMethod {
273    pub name: String,
274    pub params: Vec<TypedParam>,
275    pub return_type: Option<TypeExpr>,
276}
277
278/// A type annotation (optional, for runtime checking).
279#[derive(Debug, Clone, PartialEq)]
280pub enum TypeExpr {
281    /// A named type: int, string, float, bool, nil, list, dict, closure,
282    /// or a user-defined type name.
283    Named(String),
284    /// A union type: `string | nil`, `int | float`.
285    Union(Vec<TypeExpr>),
286    /// A dict shape type: `{name: string, age: int, active?: bool}`.
287    Shape(Vec<ShapeField>),
288    /// A list type: `list[int]`.
289    List(Box<TypeExpr>),
290    /// A dict type with key and value types: `dict[string, int]`.
291    DictType(Box<TypeExpr>, Box<TypeExpr>),
292}
293
294/// A field in a dict shape type.
295#[derive(Debug, Clone, PartialEq)]
296pub struct ShapeField {
297    pub name: String,
298    pub type_expr: TypeExpr,
299    pub optional: bool,
300}
301
302/// A parameter with an optional type annotation.
303#[derive(Debug, Clone, PartialEq)]
304pub struct TypedParam {
305    pub name: String,
306    pub type_expr: Option<TypeExpr>,
307}
308
309impl TypedParam {
310    /// Create an untyped parameter.
311    pub fn untyped(name: impl Into<String>) -> Self {
312        Self {
313            name: name.into(),
314            type_expr: None,
315        }
316    }
317
318    /// Create a typed parameter.
319    pub fn typed(name: impl Into<String>, type_expr: TypeExpr) -> Self {
320        Self {
321            name: name.into(),
322            type_expr: Some(type_expr),
323        }
324    }
325
326    /// Extract just the names from a list of typed params.
327    pub fn names(params: &[TypedParam]) -> Vec<String> {
328        params.iter().map(|p| p.name.clone()).collect()
329    }
330}
harn_parser/ast.rs

harn_parser/
ast.rs
