schala/schala-lang/language/src/scope_resolution.rs
2019-10-21 03:02:11 -07:00

114 lines
3.7 KiB
Rust

use std::rc::Rc;
use crate::symbol_table::{SymbolTable, ScopeSegment, FullyQualifiedSymbolName};
use crate::ast::*;
use crate::util::ScopeStack;
type FQSNPrefix = Vec<ScopeSegment>;
pub struct ScopeResolver<'a> {
symbol_table: &'a mut SymbolTable,
name_scope_stack: ScopeStack<'a, Rc<String>, FQSNPrefix>,
}
impl<'a> ASTVisitor for ScopeResolver<'a> {
fn import(&mut self, import_spec: &ImportSpecifier) {
let ImportSpecifier { ref path_components, ref imported_names, .. } = &import_spec;
match imported_names {
ImportedNames::All => {
let prefix = FullyQualifiedSymbolName(path_components.iter().map(|c| ScopeSegment {
name: c.clone(),
}).collect());
let members = self.symbol_table.lookup_children_of_fqsn(&prefix);
for member in members.into_iter() {
let local_name = member.0.last().unwrap().name.clone();
self.name_scope_stack.insert(local_name.clone(), member.0);
}
},
ImportedNames::LastOfPath => {
let name = path_components.last().unwrap(); //TODO handle better
let fqsn_prefix = path_components.iter().map(|c| ScopeSegment {
name: c.clone(),
}).collect();
self.name_scope_stack.insert(name.clone(), fqsn_prefix);
}
ImportedNames::List(ref names) => {
let fqsn_prefix: FQSNPrefix = path_components.iter().map(|c| ScopeSegment {
name: c.clone(),
}).collect();
for name in names.iter() {
self.name_scope_stack.insert(name.clone(), fqsn_prefix.clone());
}
}
};
}
fn qualified_name(&mut self, qualified_name: &QualifiedName) {
let fqsn = self.lookup_name_in_scope(&qualified_name);
let ref id = qualified_name.id;
self.symbol_table.map_id_to_fqsn(id, fqsn);
}
fn named_struct(&mut self, name: &QualifiedName, _fields: &Vec<(Rc<String>, Expression)>) {
let ref id = name.id;
let fqsn = self.lookup_name_in_scope(&name);
self.symbol_table.map_id_to_fqsn(id, fqsn);
}
fn pattern(&mut self, pat: &Pattern) {
use Pattern::*;
match pat {
Ignored => (),
TuplePattern(_) => (),
Literal(_) => (),
TupleStruct(name, _) => self.qualified_name_in_pattern(name),
Record(name, _) => self.qualified_name_in_pattern(name),
VarOrName(name) => self.qualified_name_in_pattern(name),
};
}
}
impl<'a> ScopeResolver<'a> {
pub fn new(symbol_table: &'a mut SymbolTable) -> ScopeResolver {
let name_scope_stack = ScopeStack::new(None);
ScopeResolver { symbol_table, name_scope_stack }
}
pub fn resolve(&mut self, ast: &mut AST) -> Result<(), String> {
walk_ast(self, ast);
Ok(())
}
fn lookup_name_in_scope(&self, sym_name: &QualifiedName) -> FullyQualifiedSymbolName {
let QualifiedName { components, .. } = sym_name;
let first_component = &components[0];
match self.name_scope_stack.lookup(first_component) {
None => {
FullyQualifiedSymbolName(components.iter().map(|name| ScopeSegment { name: name.clone() }).collect())
},
Some(fqsn_prefix) => {
let mut full_name = fqsn_prefix.clone();
let rest_of_name: FQSNPrefix = components[1..].iter().map(|name| ScopeSegment { name: name.clone() }).collect();
full_name.extend_from_slice(&rest_of_name);
FullyQualifiedSymbolName(full_name)
}
}
}
/// this might be a variable or a pattern. if a variable, set to none
fn qualified_name_in_pattern(&mut self, qualified_name: &QualifiedName) {
let ref id = qualified_name.id;
let fqsn = self.lookup_name_in_scope(qualified_name);
if self.symbol_table.lookup_by_fqsn(&fqsn).is_some() {
self.symbol_table.map_id_to_fqsn(&id, fqsn);
}
}
}
#[cfg(test)]
mod tests {
#[test]
fn basic_scope() {
}
}