schala/schala-lang/language/src/scope_resolution.rs

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use std::rc::Rc;
use crate::symbol_table::{SymbolTable, ScopeSegment, ScopeSegmentKind, FullyQualifiedSymbolName};
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use crate::ast::*;
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use crate::util::ScopeStack;
type FQSNPrefix = Vec<ScopeSegment>;
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pub struct ScopeResolver<'a> {
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symbol_table: &'a mut SymbolTable,
name_scope_stack: ScopeStack<'a, Rc<String>, FQSNPrefix>,
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}
impl<'a> ScopeResolver<'a> {
pub fn new(symbol_table: &'a mut SymbolTable) -> ScopeResolver {
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let name_scope_stack = ScopeStack::new(None);
ScopeResolver { symbol_table, name_scope_stack }
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}
pub fn resolve(&mut self, ast: &mut AST) -> Result<(), String> {
for statement in ast.statements.iter() {
match statement.kind {
StatementKind::Declaration(ref decl) => self.decl(decl),
StatementKind::Expression(ref expr) => self.expr(expr),
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StatementKind::Import(ref spec) => self.import(spec),
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}?;
}
Ok(())
}
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fn import(&mut self, import_spec: &ImportSpecifier) -> Result<(), String> {
let ImportSpecifier { ref path_components, ref imported_names, .. } = &import_spec;
match imported_names {
ImportedNames::All => unimplemented!(),
ImportedNames::LastOfPath => {
let name = path_components.last().unwrap(); //TODO handle better
let fqsn_prefix = path_components.iter().map(|c| ScopeSegment {
name: c.clone(), kind: ScopeSegmentKind::Type
}).collect();
self.name_scope_stack.insert(name.clone(), fqsn_prefix);
()
}
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ImportedNames::List(ref names) => {
let fqsn_prefix: FQSNPrefix = path_components.iter().map(|c| ScopeSegment {
name: c.clone(), kind: ScopeSegmentKind::Type
}).collect();
for name in names.iter() {
self.name_scope_stack.insert(name.clone(), fqsn_prefix.clone());
}
}
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};
Ok(())
}
fn decl(&mut self, decl: &Declaration) -> Result<(), String> {
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use Declaration::*;
match decl {
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Binding { expr, .. } => self.expr(expr),
FuncDecl(_, block) => self.block(block),
_ => Ok(()),
}
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}
fn block(&mut self, block: &Block) -> Result<(), String> {
for statement in block.iter() {
match statement.kind {
StatementKind::Declaration(ref decl) => self.decl(decl),
StatementKind::Expression(ref expr) => self.expr(expr),
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StatementKind::Import(_) => Ok(())
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}?;
}
Ok(())
}
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fn expr(&mut self, expr: &Expression) -> Result<(), String> {
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use ExpressionKind::*;
match &expr.kind {
ExpressionKind::Value(qualified_name) => {
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let fqsn = lookup_name_in_scope(&qualified_name);
let ref id = qualified_name.id;
self.symbol_table.map_id_to_fqsn(id, fqsn);
},
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NamedStruct { name, .. } => {
let ref id = name.id;
let fqsn = lookup_name_in_scope(&name);
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self.symbol_table.map_id_to_fqsn(id, fqsn);
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},
BinExp(_, ref lhs, ref rhs) => {
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self.expr(lhs)?;
self.expr(rhs)?;
},
PrefixExp(_, ref arg) => {
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self.expr(arg)?;
},
TupleLiteral(exprs) => {
for expr in exprs.iter() {
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self.expr(expr)?;
}
},
Call { f, arguments } => {
self.expr(&f)?;
for arg in arguments.iter() {
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self.invoc(arg)?;
}
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},
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Lambda { params, body, .. } => {
self.block(&body)?;
for param in params.iter() {
if let Some(ref expr) = param.default {
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self.expr(expr)?;
}
}
},
IfExpression { ref body, ref discriminator } => {
match &**discriminator {
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Discriminator::Simple(expr) | Discriminator::BinOp(expr, _) => self.expr(expr)?
};
match &**body {
IfExpressionBody::SimplePatternMatch(ref pat, ref alt1, ref alt2) => {
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self.pattern(pat)?;
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self.block(alt1)?;
if let Some(alt) = alt2 {
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self.block(alt)?;
}
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},
IfExpressionBody::GuardList(guardarms) => {
for arm in guardarms.iter() {
if let Guard::Pat(ref pat) = arm.guard {
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self.pattern(pat)?;
}
self.block(&arm.body)?;
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}
}
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_ => ()
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}
},
_ => ()
};
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Ok(())
}
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fn invoc(&mut self, invoc: &InvocationArgument) -> Result<(), String> {
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use InvocationArgument::*;
match invoc {
Positional(expr) => self.expr(expr),
Keyword { expr, .. } => self.expr(expr),
_ => Ok(())
}
}
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fn pattern(&mut self, pat: &Pattern) -> Result<(), String> {
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use Pattern::*;
match pat {
Ignored => (),
TuplePattern(patterns) => {
for pat in patterns {
self.pattern(pat)?;
}
},
Literal(_) => (),
TupleStruct(name, patterns) => {
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self.qualified_name_in_pattern(name);
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for pat in patterns {
self.pattern(pat)?;
}
},
Record(name, key_patterns) => {
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self.qualified_name_in_pattern(name);
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for (_, pat) in key_patterns {
self.pattern(pat)?;
}
},
VarOrName(name) => {
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self.qualified_name_in_pattern(name);
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},
};
Ok(())
}
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/// this might be a variable or a pattern. if a variable, set to none
fn qualified_name_in_pattern(&mut self, qualified_name: &QualifiedName) {
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let ref id = qualified_name.id;
let fqsn = lookup_name_in_scope(qualified_name);
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if self.symbol_table.lookup_by_fqsn(&fqsn).is_some() {
self.symbol_table.map_id_to_fqsn(&id, fqsn);
}
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}
}
//TODO this is incomplete
fn lookup_name_in_scope(sym_name: &QualifiedName) -> FullyQualifiedSymbolName {
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let QualifiedName { components: vec, .. } = sym_name;
let len = vec.len();
let new_vec: Vec<ScopeSegment> = vec.iter().enumerate().map(|(i, name)| {
let kind = if i == (len - 1) {
ScopeSegmentKind::Terminal
} else {
ScopeSegmentKind::Type
};
ScopeSegment { name: name.clone(), kind }
}).collect();
FullyQualifiedSymbolName(new_vec)
}
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#[cfg(test)]
mod tests {
#[test]
fn basic_scope() {
}
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}