swamp_script_analyzer/pattern.rs
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/*
* Copyright (c) Peter Bjorklund. All rights reserved. https://github.com/swamp/script
* Licensed under the MIT License. See LICENSE in the project root for license information.
*/
use crate::err::ResolveError;
use crate::Resolver;
use swamp_script_ast::{Node, NormalPattern, Pattern, PatternElement};
use swamp_script_semantic::{
ResolvedEnumVariantContainerType, ResolvedEnumVariantTypeRef, ResolvedNormalPattern,
ResolvedPattern, ResolvedPatternElement, ResolvedType,
};
use tracing::info;
impl<'a> Resolver<'a> {
fn find_variant_in_pattern(
&self,
expression_type: &ResolvedType,
ast_name: &Node,
) -> Result<ResolvedEnumVariantTypeRef, ResolveError> {
let enum_type_ref = match expression_type {
ResolvedType::Enum(enum_type_ref) => enum_type_ref,
_ => Err(ResolveError::ExpectedEnumInPattern(self.to_node(ast_name)))?,
};
let enum_name = &enum_type_ref.assigned_name;
let variant_name = self.get_text(ast_name).to_string();
self.shared
.lookup
.get_enum_variant_type(&enum_type_ref.module_path, &enum_name, &variant_name)
.map_or_else(
|| {
Err(ResolveError::UnknownEnumVariantTypeInPattern(
self.to_node(ast_name),
))
},
Ok,
)
}
pub(crate) fn resolve_pattern(
&mut self,
ast_pattern: &Pattern,
expected_condition_type: &ResolvedType,
) -> Result<(ResolvedPattern, bool), ResolveError> {
match ast_pattern {
Pattern::Wildcard(node) => Ok((ResolvedPattern::Wildcard(self.to_node(&node)), false)),
Pattern::NormalPattern(normal_pattern, maybe_guard) => {
let (normal_pattern, was_pushed) =
self.resolve_normal_pattern(normal_pattern, expected_condition_type)?;
let resolved_guard = if let Some(guard_clause) = maybe_guard {
Some(self.resolve_bool_expression(&guard_clause.0)?)
} else {
None
};
Ok((
ResolvedPattern::Normal(normal_pattern, resolved_guard),
was_pushed,
))
}
}
}
pub(crate) fn resolve_normal_pattern(
&mut self,
ast_normal_pattern: &NormalPattern,
expected_condition_type: &ResolvedType,
) -> Result<(ResolvedNormalPattern, bool), ResolveError> {
match ast_normal_pattern {
NormalPattern::PatternList(elements) => {
let mut resolved_elements = Vec::new();
let mut scope_is_pushed = false;
for element in elements {
match element {
PatternElement::Variable(var) => {
if !scope_is_pushed {
self.push_block_scope("pattern_list one variable");
scope_is_pushed = true;
}
let variable_ref =
self.create_local_variable(var, &None, expected_condition_type)?;
resolved_elements.push(ResolvedPatternElement::Variable(variable_ref));
}
PatternElement::Expression(_expr) => {
return Err(ResolveError::ExpressionsNotAllowedInLetPattern);
}
PatternElement::Wildcard(node) => {
resolved_elements
.push(ResolvedPatternElement::Wildcard(self.to_node(node)));
}
}
}
Ok((
ResolvedNormalPattern::PatternList(resolved_elements),
scope_is_pushed,
))
}
NormalPattern::EnumPattern(variant_name, maybe_elements) => {
let mut scope_was_pushed = false;
let enum_variant_type_ref =
self.find_variant_in_pattern(expected_condition_type, variant_name)?;
if let Some(elements) = maybe_elements {
let mut resolved_elements = Vec::new();
match &enum_variant_type_ref.data {
ResolvedEnumVariantContainerType::Tuple(tuple_type) => {
// For tuples, elements must be in order but can be partial
if elements.len() > tuple_type.fields_in_order.len() {
return Err(ResolveError::TooManyTupleFields {
max: tuple_type.fields_in_order.len(),
got: elements.len(),
});
}
if !scope_was_pushed {
self.push_block_scope("enum tuple");
scope_was_pushed = true;
}
// Only zip with as many fields as we have elements
for (element, field_type) in
elements.iter().zip(&tuple_type.fields_in_order)
{
match element {
PatternElement::Variable(var) => {
info!(?var, "ENUM TUPLE found variable to handle");
let variable_ref =
self.create_local_variable(var, &None, field_type)?;
resolved_elements
.push(ResolvedPatternElement::Variable(variable_ref));
}
PatternElement::Wildcard(node) => {
resolved_elements.push(ResolvedPatternElement::Wildcard(
self.to_node(node),
));
}
PatternElement::Expression(_) => {
return Err(
ResolveError::ExpressionsNotAllowedInLetPattern,
);
}
}
}
}
ResolvedEnumVariantContainerType::Struct(struct_type) => {
if !scope_was_pushed {
self.push_block_scope("enum struct");
scope_was_pushed = true;
}
// For structs, can match any subset of fields in any order
for element in elements {
match element {
PatternElement::Variable(var) => {
let var_name_str = self.get_text(var).to_string();
// Check if the field exists
let field_index = struct_type
.anon_struct
.defined_fields
.get_index(&var_name_str)
.ok_or_else(|| {
ResolveError::UnknownField(self.to_node(var))
})?;
let field_type = struct_type
.anon_struct
.defined_fields
.get(&var_name_str)
.ok_or_else(|| {
ResolveError::UnknownField(self.to_node(var))
})?;
let variable_ref = self.create_local_variable(
var,
&None,
&field_type.field_type,
)?;
resolved_elements.push(
ResolvedPatternElement::VariableWithFieldIndex(
variable_ref,
field_index,
),
);
}
PatternElement::Wildcard(node) => {
resolved_elements.push(ResolvedPatternElement::Wildcard(
self.to_node(node),
));
}
PatternElement::Expression(_) => {
return Err(
ResolveError::ExpressionsNotAllowedInLetPattern,
);
}
}
}
}
ResolvedEnumVariantContainerType::Nothing => {
if !elements.is_empty() {
return Err(ResolveError::EnumVariantHasNoFields(
self.to_node(variant_name),
));
}
}
}
Ok((
ResolvedNormalPattern::EnumPattern(
enum_variant_type_ref,
Some(resolved_elements),
),
scope_was_pushed,
))
} else {
Ok((
ResolvedNormalPattern::EnumPattern(enum_variant_type_ref, None),
false,
))
}
}
NormalPattern::Literal(ast_literal) => Ok((
self.resolve_pattern_literal(ast_literal, expected_condition_type)?,
false,
)),
}
}
}