505 lines
17 KiB
Rust
505 lines
17 KiB
Rust
//! Tools for analyzing an abstract syntax tree and catch errors before running the virtual
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//! machine.
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//!
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//! This module provides to anlysis options, both of which borrow an abstract syntax tree and a
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//! hash map of variables:
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//! - `analyze` convenience function
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//! - `Analyzer` struct
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use std::{
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error::Error,
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fmt::{self, Display, Formatter},
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};
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use crate::{
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abstract_tree::BinaryOperator, AbstractSyntaxTree, BuiltInFunction, Context, Node, Span,
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Statement, Type,
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};
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/// Analyzes the abstract syntax tree for errors.
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///
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/// # Examples
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/// ```
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/// # use std::collections::HashMap;
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/// # use dust_lang::*;
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/// let input = "x = 1 + false";
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/// let abstract_tree = parse(input).unwrap();
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/// let mut context = Context::new();
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/// let result = analyze(&abstract_tree, &mut context);
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///
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/// assert!(result.is_err());
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/// ```
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pub fn analyze(
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abstract_tree: &AbstractSyntaxTree,
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context: &mut Context,
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) -> Result<(), AnalyzerError> {
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let mut analyzer = Analyzer::new(abstract_tree, context);
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analyzer.analyze()
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}
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/// Static analyzer that checks for potential runtime errors.
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///
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/// # Examples
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/// ```
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/// # use std::collections::HashMap;
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/// # use dust_lang::*;
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/// let input = "x = 1 + false";
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/// let abstract_tree = parse(input).unwrap();
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/// let mut context = Context::new();
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/// let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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/// let result = analyzer.analyze();
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///
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/// assert!(result.is_err());
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pub struct Analyzer<'a> {
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abstract_tree: &'a AbstractSyntaxTree,
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context: &'a mut Context,
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}
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impl<'a> Analyzer<'a> {
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pub fn new(abstract_tree: &'a AbstractSyntaxTree, context: &'a mut Context) -> Self {
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Self {
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abstract_tree,
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context,
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}
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}
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pub fn analyze(&mut self) -> Result<(), AnalyzerError> {
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for node in &self.abstract_tree.nodes {
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self.analyze_node(node)?;
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}
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Ok(())
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}
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fn analyze_node(&mut self, node: &Node<Statement>) -> Result<(), AnalyzerError> {
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match &node.inner {
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Statement::BinaryOperation {
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left,
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operator,
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right,
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} => {
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if let BinaryOperator::Assign = operator.inner {
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if let Statement::Identifier(identifier) = &left.inner {
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self.analyze_node(right)?;
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let right_type = right.inner.expected_type(self.context);
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self.context.set_type(
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identifier.clone(),
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right_type.ok_or(AnalyzerError::ExpectedValue {
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actual: right.as_ref().clone(),
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position: right.position,
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})?,
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);
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return Ok(());
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}
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}
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self.analyze_node(left)?;
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self.analyze_node(right)?;
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let left_type = left.inner.expected_type(self.context);
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let right_type = right.inner.expected_type(self.context);
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if let BinaryOperator::Add
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| BinaryOperator::Subtract
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| BinaryOperator::Multiply
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| BinaryOperator::Divide
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| BinaryOperator::Greater
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| BinaryOperator::GreaterOrEqual
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| BinaryOperator::Less
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| BinaryOperator::LessOrEqual = operator.inner
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{
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match (left_type, right_type) {
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(Some(Type::Integer), Some(Type::Integer)) => {}
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(Some(Type::Float), Some(Type::Float)) => {}
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(Some(Type::String), Some(Type::String)) => {}
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(Some(Type::Integer), _) => {
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return Err(AnalyzerError::ExpectedInteger {
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actual: right.as_ref().clone(),
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position: right.position,
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});
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}
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(Some(Type::Float), _) => {
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return Err(AnalyzerError::ExpectedFloat {
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actual: right.as_ref().clone(),
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position: right.position,
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});
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}
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(Some(Type::String), _) => {
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return Err(AnalyzerError::ExpectedString {
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actual: right.as_ref().clone(),
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position: right.position,
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});
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}
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(_, _) => {
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return Err(AnalyzerError::ExpectedIntegerFloatOrString {
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actual: right.as_ref().clone(),
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position: right.position,
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})
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}
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}
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}
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}
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Statement::Block(statements) => {
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for statement in statements {
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self.analyze_node(statement)?;
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}
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}
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Statement::BuiltInFunctionCall { .. } => {}
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Statement::Constant(_) => {}
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Statement::FunctionCall { function, .. } => {
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if let Statement::Identifier(_) = &function.inner {
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// Function is in the correct position
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} else {
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return Err(AnalyzerError::ExpectedIdentifier {
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actual: function.as_ref().clone(),
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position: function.position,
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});
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}
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}
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Statement::Identifier(identifier) => {
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let exists = self.context.add_allowed_use(identifier);
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if !exists {
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return Err(AnalyzerError::UndefinedVariable {
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identifier: node.clone(),
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});
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}
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}
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Statement::List(statements) => {
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for statement in statements {
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self.analyze_node(statement)?;
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}
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}
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Statement::Map(properties) => {
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for (_key, value_node) in properties {
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self.analyze_node(value_node)?;
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}
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}
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Statement::Nil(node) => {
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self.analyze_node(node)?;
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}
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Statement::PropertyAccess(left, right) => {
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if let Statement::Identifier(_) | Statement::Constant(_) | Statement::List(_) =
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&left.inner
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{
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// Left side is valid
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} else {
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return Err(AnalyzerError::ExpectedValue {
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actual: left.as_ref().clone(),
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position: left.position,
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});
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}
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if let Statement::BuiltInFunctionCall { function, .. } = &right.inner {
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if function == &BuiltInFunction::IsEven || function == &BuiltInFunction::IsOdd {
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if let Some(Type::Integer) = left.inner.expected_type(self.context) {
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} else {
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return Err(AnalyzerError::ExpectedIntegerOrFloat {
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actual: left.as_ref().clone(),
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position: left.position,
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});
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}
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}
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}
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self.analyze_node(right)?;
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}
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Statement::While { condition, body } => {
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self.analyze_node(condition)?;
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self.analyze_node(body)?;
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if let Some(Type::Boolean) = condition.inner.expected_type(self.context) {
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} else {
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return Err(AnalyzerError::ExpectedBoolean {
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actual: condition.as_ref().clone(),
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position: condition.position,
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});
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}
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}
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}
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Ok(())
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}
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}
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#[derive(Clone, Debug, PartialEq)]
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pub enum AnalyzerError {
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ExpectedBoolean {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedFloat {
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actual: Node<Statement>,
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position: (usize, usize),
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},
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ExpectedFunction {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedIdentifier {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedInteger {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedIntegerOrFloat {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedIntegerFloatOrString {
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actual: Node<Statement>,
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position: Span,
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},
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ExpectedString {
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actual: Node<Statement>,
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position: (usize, usize),
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},
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ExpectedValue {
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actual: Node<Statement>,
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position: Span,
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},
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UndefinedVariable {
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identifier: Node<Statement>,
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},
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UnexpectedIdentifier {
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identifier: Node<Statement>,
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position: Span,
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},
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UnexectedString {
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actual: Node<Statement>,
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position: (usize, usize),
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},
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}
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impl AnalyzerError {
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pub fn position(&self) -> Span {
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match self {
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AnalyzerError::ExpectedBoolean { position, .. } => *position,
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AnalyzerError::ExpectedFloat { position, .. } => *position,
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AnalyzerError::ExpectedFunction { position, .. } => *position,
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AnalyzerError::ExpectedIdentifier { position, .. } => *position,
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AnalyzerError::ExpectedValue { position, .. } => *position,
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AnalyzerError::ExpectedInteger { position, .. } => *position,
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AnalyzerError::ExpectedIntegerOrFloat { position, .. } => *position,
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AnalyzerError::ExpectedIntegerFloatOrString { position, .. } => *position,
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AnalyzerError::ExpectedString { position, .. } => *position,
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AnalyzerError::UndefinedVariable { identifier } => identifier.position,
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AnalyzerError::UnexpectedIdentifier { position, .. } => *position,
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AnalyzerError::UnexectedString { position, .. } => *position,
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}
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}
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}
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impl Error for AnalyzerError {}
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impl Display for AnalyzerError {
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fn fmt(&self, f: &mut Formatter) -> fmt::Result {
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match self {
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AnalyzerError::ExpectedBoolean { actual, .. } => {
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write!(f, "Expected boolean, found {}", actual)
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}
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AnalyzerError::ExpectedFunction { actual, .. } => {
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write!(f, "Expected function, found {}", actual)
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}
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AnalyzerError::ExpectedFloat { actual, .. } => {
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write!(f, "Expected float, found {}", actual)
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}
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AnalyzerError::ExpectedIdentifier { actual, .. } => {
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write!(f, "Expected identifier, found {}", actual)
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}
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AnalyzerError::ExpectedInteger { actual, .. } => {
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write!(f, "Expected integer, found {}", actual)
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}
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AnalyzerError::ExpectedIntegerOrFloat { actual, .. } => {
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write!(f, "Expected integer or float, found {}", actual)
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}
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AnalyzerError::ExpectedIntegerFloatOrString { actual, .. } => {
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write!(f, "Expected integer, float, or string, found {}", actual)
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}
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AnalyzerError::ExpectedString { actual, .. } => {
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write!(f, "Expected string, found {}", actual)
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}
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AnalyzerError::ExpectedValue { actual, .. } => {
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write!(f, "Expected value, found {}", actual)
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}
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AnalyzerError::UndefinedVariable { identifier } => {
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write!(f, "Undefined variable {}", identifier)
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}
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AnalyzerError::UnexpectedIdentifier { identifier, .. } => {
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write!(f, "Unexpected identifier {}", identifier)
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}
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AnalyzerError::UnexectedString { actual, .. } => {
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write!(f, "Unexpected string {}", actual)
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}
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use crate::{BuiltInFunction, Identifier, Value};
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use super::*;
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#[test]
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fn math_requires_same_types() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::BinaryOperation {
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left: Box::new(Node::new(Statement::Constant(Value::integer(1)), (0, 1))),
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operator: Node::new(BinaryOperator::Add, (1, 2)),
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right: Box::new(Node::new(Statement::Constant(Value::float(1.0)), (3, 4))),
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},
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(0, 2),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::ExpectedInteger {
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actual: Node::new(Statement::Constant(Value::float(1.0)), (3, 4)),
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position: (3, 4)
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})
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)
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}
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#[test]
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fn float_plus_integer() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::BinaryOperation {
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left: Box::new(Node::new(Statement::Constant(Value::float(1.0)), (0, 1))),
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operator: Node::new(BinaryOperator::Add, (1, 2)),
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right: Box::new(Node::new(Statement::Constant(Value::integer(1)), (3, 4))),
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},
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(0, 2),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::ExpectedFloat {
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actual: Node::new(Statement::Constant(Value::integer(1)), (3, 4)),
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position: (3, 4)
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})
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)
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}
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#[test]
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fn integer_plus_boolean() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::BinaryOperation {
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left: Box::new(Node::new(Statement::Constant(Value::integer(1)), (0, 1))),
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operator: Node::new(BinaryOperator::Add, (1, 2)),
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right: Box::new(Node::new(Statement::Constant(Value::boolean(true)), (3, 4))),
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},
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(0, 2),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::ExpectedInteger {
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actual: Node::new(Statement::Constant(Value::boolean(true)), (3, 4)),
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position: (3, 4)
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})
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)
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}
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#[test]
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fn is_even_expects_number() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::PropertyAccess(
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Box::new(Node::new(Statement::Constant(Value::boolean(true)), (0, 1))),
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Box::new(Node::new(
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Statement::BuiltInFunctionCall {
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function: BuiltInFunction::IsEven,
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type_arguments: None,
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value_arguments: None,
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},
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(1, 2),
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)),
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),
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(0, 2),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::ExpectedIntegerOrFloat {
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actual: Node::new(Statement::Constant(Value::boolean(true)), (0, 1)),
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position: (0, 1)
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})
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)
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}
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#[test]
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fn is_odd_expects_number() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::PropertyAccess(
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Box::new(Node::new(Statement::Constant(Value::boolean(true)), (0, 1))),
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Box::new(Node::new(
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Statement::BuiltInFunctionCall {
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function: BuiltInFunction::IsOdd,
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type_arguments: None,
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value_arguments: None,
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},
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(1, 2),
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)),
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),
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(0, 2),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::ExpectedIntegerOrFloat {
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actual: Node::new(Statement::Constant(Value::boolean(true)), (0, 1)),
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position: (0, 1)
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})
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)
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}
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#[test]
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fn undefined_variable() {
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let abstract_tree = AbstractSyntaxTree {
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nodes: [Node::new(
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Statement::Identifier(Identifier::new("x")),
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(0, 1),
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)]
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.into(),
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};
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let mut context = Context::new();
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let mut analyzer = Analyzer::new(&abstract_tree, &mut context);
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assert_eq!(
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analyzer.analyze(),
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Err(AnalyzerError::UndefinedVariable {
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identifier: Node::new(Statement::Identifier(Identifier::new("x")), (0, 1))
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})
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)
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}
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}
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