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use std::collections::BTreeMap;
use base::ast::Visitor;
use base::ast::{
self, Argument, AstType, Commented, Expr, Pattern, SpannedExpr, SpannedPattern, ValueBinding,
};
use base::fnv::FnvMap;
use base::metadata::{Metadata, MetadataEnv};
use base::symbol::{Name, Symbol};
use base::types::row_iter;
struct Environment<'b> {
env: &'b MetadataEnv,
stack: FnvMap<Symbol, Metadata>,
}
pub fn metadata(
env: &MetadataEnv,
expr: &SpannedExpr<Symbol>,
) -> (Metadata, FnvMap<Symbol, Metadata>) {
struct MetadataVisitor<'b> {
env: Environment<'b>,
}
impl<'b> MetadataVisitor<'b> {
fn new_binding(&mut self, metadata: Metadata, bind: &ValueBinding<Symbol>) {
match bind.name.value {
Pattern::As(ref id, _) => {
let metadata = bind.metadata.clone().merge(metadata);
self.stack_var(id.clone(), metadata.clone());
self.new_pattern(metadata, &bind.name);
}
Pattern::Ident(ref id) => {
let mut metadata = bind.metadata.clone().merge(metadata);
metadata.args = bind
.args
.iter()
.filter(|arg| !arg.name.value.name.definition_name().starts_with("__"))
.map(|arg| Argument {
name: arg.name.value.name.clone(),
arg_type: arg.arg_type,
})
.collect();
if let Some(type_metadata) = id
.typ
.remove_forall_and_implicit_args()
.alias_ident()
.and_then(|id| self.metadata(id))
{
metadata.merge_with(type_metadata.clone());
}
self.stack_var(id.name.clone(), metadata);
}
Pattern::Constructor(..)
| Pattern::Tuple { .. }
| Pattern::Record { .. }
| Pattern::Literal(_)
| Pattern::Error => self.new_pattern(metadata, &bind.name),
}
}
fn new_pattern(&mut self, mut metadata: Metadata, pattern: &SpannedPattern<Symbol>) {
match pattern.value {
Pattern::Record {
ref fields,
ref types,
ref typ,
ref implicit_import,
} => {
if let Some(ref implicit_import) = *implicit_import {
self.stack_var(implicit_import.value.clone(), metadata.clone());
}
for field in fields {
if let Some(m) = metadata.module.remove(field.name.value.as_ref()) {
let id = match field.value {
Some(ref pat) => match pat.value {
Pattern::Ident(ref id) => &id.name,
_ => return self.new_pattern(m, pat),
},
None => &field.name.value,
};
self.stack_var(id.clone(), m);
}
}
for field in types {
if let Some(m) = metadata.module.remove(field.name.value.as_ref()) {
if let Some(type_field) = typ
.type_field_iter()
.find(|type_field| type_field.name.name_eq(&field.name.value))
{
self.stack_var(type_field.typ.name.clone(), m.clone());
}
let id = field
.value
.as_ref()
.unwrap_or_else(|| &field.name.value)
.clone();
self.stack_var(id, m);
}
}
}
Pattern::Ident(ref id) => self.stack_var(id.name.clone(), metadata),
Pattern::As(ref id, ref pat) => {
self.stack_var(id.clone(), metadata.clone());
self.new_pattern(metadata, pat);
}
Pattern::Tuple { .. }
| Pattern::Constructor(..)
| Pattern::Literal(_)
| Pattern::Error => (),
}
}
fn stack_var(&mut self, id: Symbol, metadata: Metadata) {
if metadata.has_data() {
debug!("Insert {}", id);
self.env.stack.insert(id, metadata);
}
}
fn metadata(&self, id: &Symbol) -> Option<&Metadata> {
debug!("Lookup {}", id);
self.env
.stack
.get(id)
.or_else(|| self.env.env.get_metadata(id))
}
fn metadata_binding(&mut self, bind: &ValueBinding<Symbol>) -> Metadata {
for arg in &bind.args {
if let Some(type_metadata) = arg
.name
.value
.typ
.alias_ident()
.and_then(|id| self.metadata(id))
.cloned()
{
self.stack_var(arg.name.value.name.clone(), type_metadata);
}
}
self.metadata_expr(&bind.expr)
}
fn metadata_expr(&mut self, expr: &SpannedExpr<Symbol>) -> Metadata {
match expr.value {
Expr::Ident(ref id) => self
.metadata(&id.name)
.cloned()
.unwrap_or_else(Metadata::default),
Expr::Record {
ref exprs,
ref types,
..
} => {
let mut module = BTreeMap::new();
for field in exprs {
let maybe_metadata = match field.value {
Some(ref expr) => {
let m = self.metadata_expr(expr);
if m.has_data() {
Some(m)
} else {
None
}
}
None => self.metadata(&field.name.value).cloned(),
};
let field_metadata = field.metadata.clone();
let maybe_metadata = match maybe_metadata {
Some(r) => field_metadata.merge(r),
None => field_metadata,
};
if maybe_metadata.has_data() {
let field_name = String::from(field.name.value.as_ref());
module.insert(field_name, maybe_metadata);
}
}
for field in types {
let maybe_metadata = self.metadata(&field.name.value).cloned();
if let Some(metadata) = maybe_metadata {
let name = Name::new(field.name.value.as_ref()).name().as_str();
module.insert(String::from(name), metadata);
}
}
Metadata {
module,
..Metadata::default()
}
}
Expr::LetBindings(ref bindings, ref expr) => {
let is_recursive = bindings.iter().all(|bind| !bind.args.is_empty());
if is_recursive {
for bind in bindings {
self.new_binding(Metadata::default(), bind);
}
for bind in bindings {
let expr_metadata = self.metadata_binding(&bind);
if let Pattern::Ident(ref id) = bind.name.value {
if expr_metadata.has_data() {
self.env
.stack
.entry(id.name.clone())
.or_insert_with(Default::default)
.merge_with(expr_metadata);
}
}
}
} else {
for bind in bindings {
let metadata = self.metadata_binding(&bind);
self.new_binding(metadata, bind);
}
}
let result = self.metadata_expr(expr);
result
}
Expr::TypeBindings(ref bindings, ref expr) => {
for bind in bindings {
let mut type_metadata =
Self::metadata_of_type(bind.alias.value.aliased_type());
let metadata = type_metadata.map_or_else(
|| bind.metadata.clone(),
|m| m.merge(bind.metadata.clone()),
);
if metadata.has_data() {
self.stack_var(bind.alias.value.name.clone(), metadata.clone());
self.stack_var(bind.name.value.clone(), metadata);
}
}
let result = self.metadata_expr(expr);
result
}
Expr::Projection(ref expr, ref field, _) => {
let metadata = self.metadata_expr(expr);
metadata
.module
.get(field.definition_name())
.cloned()
.unwrap_or_default()
}
Expr::MacroExpansion {
ref replacement, ..
} => self.metadata_expr(replacement),
_ => {
ast::walk_expr(self, expr);
Metadata::default()
}
}
}
fn metadata_of_type(typ: &AstType<Symbol>) -> Option<Metadata> {
let module: BTreeMap<_, _> = row_iter(typ)
.filter_map(|field| {
let field_metadata = Self::metadata_of_type(&field.typ);
let field_metadata = match field.typ.comment() {
Some(comment) => {
let mut metadata = field_metadata.unwrap_or_default();
metadata.comment = Some(comment.clone());
Some(metadata)
}
None => field_metadata,
};
field_metadata.map(|m| (field.name.to_string(), m))
})
.collect();
if module.is_empty() {
None
} else {
Some(Metadata {
module,
..Metadata::default()
})
}
}
}
impl<'a, 'b> Visitor<'a> for MetadataVisitor<'b> {
type Ident = Symbol;
fn visit_expr(&mut self, expr: &SpannedExpr<Symbol>) {
self.metadata_expr(expr);
}
}
let mut visitor = MetadataVisitor {
env: Environment {
env: env,
stack: FnvMap::default(),
},
};
let metadata = visitor.metadata_expr(expr);
(metadata, visitor.env.stack)
}