Add a variable assignment statement

Cargo.lock

@@ -150,6 +150,7 @@ dependencies = [
  "color-eyre",
  "dotenv",
  "from_variants",
+ "itertools",
  "match_any",
  "tracing",
  "tracing-subscriber",
@@ -196,6 +197,12 @@ version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77c90badedccf4105eca100756a0b1289e191f6fcbdadd3cee1d2f614f97da8f"
 
+[[package]]
+name = "either"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+
 [[package]]
 name = "eyre"
 version = "0.6.7"
@@ -282,6 +289,15 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9a9d19fa1e79b6215ff29b9d6880b706147f16e9b1dbb1e4e5947b5b02bc5e3"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"

Cargo.toml

@@ -8,6 +8,7 @@ clap = { version = "3.1.9", features = ["derive"] }
 color-eyre = "0.6.1"
 dotenv = "0.15.0"
 from_variants = "1.0.0"
+itertools = "0.10.3"
 match_any = "1.0.1"
 tracing = "0.1.32"
 tracing-subscriber = { version = "0.3.9", features = ["env-filter"] }

src/ast/ast_parser_iter.rs

@@ -0,0 +1,37 @@
+use itertools::{peek_nth, PeekNth, PeekingNext};
+
+pub struct ParserIter<T: Iterator>(PeekNth<T>);
+
+impl<T: Iterator> ParserIter<T> {
+	pub fn new(iter: T) -> ParserIter<T> {
+		ParserIter(peek_nth(iter))
+	}
+
+	pub fn next(&mut self) -> T::Item {
+		self.0.next().unwrap()
+	}
+
+	pub fn peek_nth(&mut self, n: usize) -> &T::Item {
+		self.0.peek_nth(n).unwrap()
+	}
+	pub fn peek(&mut self) -> &T::Item {
+		self.peek_nth(0)
+	}
+}
+
+impl<T: Iterator> Iterator for ParserIter<T> {
+	type Item = T::Item;
+
+	fn next(&mut self) -> Option<Self::Item> {
+		Some(self.next())
+	}
+}
+
+impl<T: Iterator> PeekingNext for ParserIter<T> {
+	fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+	where
+		F: FnOnce(&Self::Item) -> bool,
+	{
+		self.0.peeking_next(accept)
+	}
+}

src/ast/expression/expression_node.rs

@@ -120,7 +120,7 @@ pub enum Literal {
 	Int(i32),
 	Float(f32),
 	Bool(bool),
-	Nil
+	Nil,
 }
 
 pub struct BinaryExpr {

src/ast/expression/expression_parser.rs

@@ -1,3 +1,5 @@
+use itertools::PeekingNext;
+
 use crate::lexer::token::{self, TokenType};
 
 use super::super::parser::{InnerASTParsingError, Parser, Result};
@@ -12,7 +14,7 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 		let mut node = self.comparison()?;
 		while let Some(o) = self
 			.token_iter
-			.next_if(|t| matches!(t.token_type, TokenType::EqualEqual | TokenType::BangEqual))
+			.peeking_next(|t| matches!(t.token_type, TokenType::EqualEqual | TokenType::BangEqual))
 		{
 			node = BinaryExpr::new(
 				Box::new(node),
@@ -27,7 +29,7 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 	fn comparison(&mut self) -> Result<ExpressionNode> {
 		let mut node = self.term()?;
 
-		while let Some(o) = self.token_iter.next_if(|t| {
+		while let Some(o) = self.token_iter.peeking_next(|t| {
 			matches!(
 				t.token_type,
 				TokenType::Greater
@@ -50,7 +52,7 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 
 		while let Some(o) = self
 			.token_iter
-			.next_if(|t| matches!(t.token_type, TokenType::Minus | TokenType::Plus))
+			.peeking_next(|t| matches!(t.token_type, TokenType::Minus | TokenType::Plus))
 		{
 			node = BinaryExpr::new(
 				Box::new(node),
@@ -67,7 +69,7 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 
 		while let Some(o) = self
 			.token_iter
-			.next_if(|t| matches!(t.token_type, TokenType::Star | TokenType::Slash))
+			.peeking_next(|t| matches!(t.token_type, TokenType::Star | TokenType::Slash))
 		{
 			node = BinaryExpr::new(
 				Box::new(node),
@@ -82,7 +84,7 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 	fn unary(&mut self) -> Result<ExpressionNode> {
 		if let Some(op) = self
 			.token_iter
-			.next_if(|t| matches!(t.token_type, TokenType::Bang | TokenType::Minus))
+			.peeking_next(|t| matches!(t.token_type, TokenType::Bang | TokenType::Minus))
 		{
 			let right = Box::new(self.unary()?);
 			Ok(ExpressionNode::UnaryExpr(UnaryExpr::new(
@@ -95,30 +97,26 @@ impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 	}
 
 	fn primary(&mut self) -> Result<ExpressionNode> {
-		let node = match self.token_iter.next() {
-			Some(token) => match token.token_type {
-				TokenType::False => ExpressionNode::Literal(Literal::Bool(false)),
-				TokenType::True => ExpressionNode::Literal(Literal::Bool(true)),
-				TokenType::Int(i) => ExpressionNode::Literal(Literal::Int(i)),
-				TokenType::String(i) => ExpressionNode::Literal(Literal::String(i)),
-				TokenType::Float(f) => ExpressionNode::Literal(Literal::Float(f)),
-				TokenType::Nil => ExpressionNode::Literal(Literal::Nil),
-				TokenType::LeftParen => {
-					let expr = self.expression()?;
-					let group = GroupingExpr::new(Box::new(expr));
-					match self
-						.token_iter
-						.next_if(|v| matches!(v.token_type, TokenType::RightParen))
-					{
-						Some(_) => return Ok(group.into()),
-						None => {
-							return Err(token.location.wrap(InnerASTParsingError::UnmatchedBrace))
-						}
-					}
+		let token = self.token_iter.next();
+		let node = match token.token_type {
+			TokenType::False => ExpressionNode::Literal(Literal::Bool(false)),
+			TokenType::True => ExpressionNode::Literal(Literal::Bool(true)),
+			TokenType::Int(i) => ExpressionNode::Literal(Literal::Int(i)),
+			TokenType::String(i) => ExpressionNode::Literal(Literal::String(i)),
+			TokenType::Float(f) => ExpressionNode::Literal(Literal::Float(f)),
+			TokenType::Nil => ExpressionNode::Literal(Literal::Nil),
+			TokenType::LeftParen => {
+				let expr = self.expression()?;
+				let group = GroupingExpr::new(Box::new(expr));
+				match self
+					.token_iter
+					.peeking_next(|v| matches!(v.token_type, TokenType::RightParen))
+				{
+					Some(_) => return Ok(group.into()),
+					None => return Err(token.location.wrap(InnerASTParsingError::UnmatchedBrace)),
 				}
-				a => return Err(token.location.wrap(InnerASTParsingError::IncorrectToken(a))),
-			},
-			None => todo!(),
+			}
+			a => return Err(token.location.wrap(InnerASTParsingError::IncorrectToken(a))),
 		};
 		Ok(node)
 	}

src/ast/mod.rs

@@ -1,3 +1,4 @@
+mod ast_parser_iter;
 pub mod expression;
-pub mod statement;
 pub mod parser;
+pub mod statement;

src/ast/parser.rs

@@ -1,15 +1,14 @@
-use super::expression::expression_node;
+use super::ast_parser_iter::ParserIter;
 use super::statement::statement_node;
 use crate::error::ErrorLocationWrapper;
 use crate::lexer::{token, token::TokenType};
-
-use std::iter;
 use std::result::Result as StdResult;
 
 #[derive(Debug)]
 pub enum InnerASTParsingError {
 	IncorrectToken(TokenType),
 	UnmatchedBrace,
+	ExpectedSemi,
 }
 
 impl std::fmt::Display for InnerASTParsingError {
@@ -17,6 +16,7 @@ impl std::fmt::Display for InnerASTParsingError {
 		match *self {
 			Self::UnmatchedBrace => write!(f, "Unmatched brace"),
 			Self::IncorrectToken(ref token) => write!(f, "Incorrect token {:?}", token),
+			Self::ExpectedSemi => write!(f, "Expected semicolon"),
 		}
 	}
 }
@@ -26,7 +26,7 @@ pub type ASTParsingError = ErrorLocationWrapper<InnerASTParsingError>;
 pub(super) type Result<T> = StdResult<T, ASTParsingError>;
 
 pub struct Parser<'a, T: Iterator<Item = token::Token<'a>>> {
-	pub(super) token_iter: iter::Peekable<T>,
+	pub(super) token_iter: super::ast_parser_iter::ParserIter<T>,
 }
 
 pub type ParseAllResult = StdResult<Vec<statement_node::Statement>, Vec<ASTParsingError>>;
@@ -34,13 +34,13 @@ pub type ParseAllResult = StdResult<Vec<statement_node::Statement>, Vec<ASTParsi
 impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 	pub fn new(iter: T) -> Parser<'a, T> {
 		Parser {
-			token_iter: iter.peekable(),
+			token_iter: ParserIter::new(iter),
 		}
 	}
 	pub fn parse_all(&mut self) -> ParseAllResult {
 		let mut res = Ok(Vec::new());
 
-		while !matches!(self.token_iter.peek().unwrap().token_type, token::TokenType::Eof) {
+		while !matches!(self.token_iter.peek().token_type, token::TokenType::Eof) {
 			match self.statement() {
 				Ok(s) => {
 					if let Ok(ref mut v) = res {

src/ast/statement/statement_node.rs

@@ -5,6 +5,7 @@ use from_variants::FromVariants;
 pub enum Statement {
 	Expression(ExpressionStatement),
 	Print(PrintStatement),
+	VariableAssignment(VariableAssignmentStatement),
 }
 
 macro_rules! all_variants {
@@ -12,7 +13,7 @@ macro_rules! all_variants {
 		{
 		use match_any::match_any;
 		use $crate::ast::statement::statement_node::*;
-		match_any!($expr, Statement::Expression($val_name) | Statement::Print($val_name) => $expr_arm)
+		match_any!($expr, Statement::Expression($val_name) | Statement::Print($val_name) | Statement::VariableAssignment($val_name) => $expr_arm)
 		}
 	};
 }
@@ -33,3 +34,15 @@ impl PrintStatement {
 		Self(expr)
 	}
 }
+
+#[derive(Debug)]
+pub struct VariableAssignmentStatement {
+	pub var_name: String,
+	pub node: ExpressionNode,
+}
+
+impl VariableAssignmentStatement {
+	pub fn new(var_name: String, node: ExpressionNode) -> Self {
+		Self { var_name, node }
+	}
+}

src/ast/statement/statement_parser.rs

@@ -1,37 +1,70 @@
-use super::statement_node::{ExpressionStatement, Statement, PrintStatement};
+use itertools::PeekingNext;
+
+use super::statement_node::{ExpressionStatement, PrintStatement, Statement};
 use crate::{
-	ast::parser::{ASTParsingError, Parser, Result},
-	lexer::token,
+	ast::{
+		parser::{InnerASTParsingError, Parser, Result},
+		statement::statement_node::VariableAssignmentStatement,
+	},
+	lexer::token::{self, Token, TokenType},
 };
 
 impl<'a, T: Iterator<Item = token::Token<'a>>> Parser<'a, T> {
 	pub fn statement(&mut self) -> Result<Statement> {
-		if let Some(_) = self
+		self.print_statement()
+	}
+
+	fn print_statement(&mut self) -> Result<Statement> {
+		if let Some(Token { location: loc, .. }) = self
 			.token_iter
-			.next_if(|t| matches!(t.token_type, token::TokenType::Print))
+			.peeking_next(|t| matches!(t.token_type, token::TokenType::Print))
 		{
-			self.print_statement()
+			let expr = self.expression()?;
+			if let token::TokenType::Semicolon = self.token_iter.peek().token_type {
+				self.token_iter.next();
+				Ok(PrintStatement::new(expr).into())
+			} else {
+				Err(loc.wrap(InnerASTParsingError::ExpectedSemi))
+			}
 		} else {
-			self.expression_statement()
+			self.variable_assignment_statement()
 		}
 	}
-	fn print_statement(&mut self) -> Result<Statement> {
-		let expr = self.expression()?;
-		if let token::TokenType::Semicolon = self.token_iter.peek().unwrap().token_type {
+
+	fn variable_assignment_statement(&mut self) -> Result<Statement> {
+		if matches!(
+			self.token_iter.peek_nth(0).token_type,
+			TokenType::Identifier(_)
+		) && matches!(self.token_iter.peek_nth(1).token_type, TokenType::Equal)
+		{
+			let ident = if let TokenType::Identifier(ident) = self.token_iter.next().token_type {
+				ident
+			} else {
+				unreachable!()
+			};
 			self.token_iter.next();
-			Ok(PrintStatement::new(expr).into())
+			let expr = self.expression()?;
+
+			let token = self.token_iter.peek();
+			if let token::TokenType::Semicolon = token.token_type {
+				self.token_iter.next();
+				Ok(VariableAssignmentStatement::new(ident, expr).into())
+			} else {
+				Err(token.location.wrap(InnerASTParsingError::ExpectedSemi))
+			}
 		} else {
-			panic!();
+			self.expression_statement()
 		}
 	}
 
 	fn expression_statement(&mut self) -> Result<Statement> {
 		let expr = self.expression()?;
-		if let token::TokenType::Semicolon = self.token_iter.peek().unwrap().token_type {
+		let token = self.token_iter.peek();
+		if let TokenType::Semicolon = token.token_type {
 			self.token_iter.next();
 			Ok(ExpressionStatement::new(expr).into())
 		} else {
-			panic!();
+			Err(token.location.wrap(InnerASTParsingError::ExpectedSemi))
 		}
 	}
 }

src/interpreter/ast_walker/expression_interpreter.rs

@@ -1,9 +1,7 @@
-use super::{RuntimeError, types::Value};
 use super::Interpret;
+use super::{types::Value, RuntimeError};
 use crate::ast::expression::expression_node;
 
-
-
 impl Interpret for expression_node::ExpressionNode {
 	fn interpret(&self) -> Result<Value, RuntimeError> {
 		expression_node::all_variants!(self, n => n.interpret())

src/interpreter/ast_walker/mod.rs

@@ -1,7 +1,7 @@
 mod expression_interpreter;
 mod statement_interpreter;
-pub use super::{error::RuntimeError, types};
 use super::types::Value;
+pub use super::{error::RuntimeError, types};
 
 pub trait Interpret {
 	fn interpret(&self) -> Result<Value, RuntimeError>;

src/interpreter/ast_walker/statement_interpreter.rs

@@ -1,26 +1,30 @@
-use super::{RuntimeError, types::Value};
 use super::Interpret;
+use super::{types::Value, RuntimeError};
 use crate::ast::statement::statement_node;
 
-
-
 impl Interpret for statement_node::Statement {
 	fn interpret(&self) -> Result<Value, RuntimeError> {
 		statement_node::all_variants!(self, n => n.interpret())
 	}
 }
 
-
 impl Interpret for statement_node::PrintStatement {
-    fn interpret(&self) -> Result<Value, RuntimeError> {
+	fn interpret(&self) -> Result<Value, RuntimeError> {
 		let res = self.0.interpret()?;
 		println!("{:?}", res);
 		Ok(res)
-    }
+	}
 }
 
 impl Interpret for statement_node::ExpressionStatement {
-    fn interpret(&self) -> Result<Value, RuntimeError> {
+	fn interpret(&self) -> Result<Value, RuntimeError> {
 		self.0.interpret()
-    }
+	}
+}
+
+impl Interpret for statement_node::VariableAssignmentStatement {
+	fn interpret(&self) -> Result<Value, RuntimeError> {
+		let expr_val = self.node.interpret()?;
+		Ok(expr_val)
+	}
 }

src/interpreter/environment.rs

@@ -1,3 +0,0 @@
-struct Environment {
-
-}

src/interpreter/mod.rs

@@ -1,4 +1,3 @@
 pub mod ast_walker;
-pub mod types;
 pub mod error;
-mod environment;
+pub mod types;

src/lexer/lexer_iter.rs

@@ -42,17 +42,24 @@ impl<'a> LexerIter<'a> {
 
 	pub fn as_str_while<F: FnMut(char) -> bool>(&mut self, mut predicate: F) -> &'a str {
 		let str = self.inner.as_str();
-		let mut end_indice = 0;
-		for (i, c) in str.char_indices() {
-			end_indice = i;
-			if !predicate(c) {
-				break;
+
+		let mut iter = str.char_indices();
+		let end_indice = loop {
+			match iter.next() {
+				Some((i, c)) => {
+					if !predicate(c) {
+						break i;
+					}
+				}
+				None => {
+					break iter.offset();
+				}
 			}
-		}
+		};
 		unsafe {
 			self.inner = str.get_unchecked(end_indice..).chars();
-			let res = str.get_unchecked(0..end_indice);
-			res
+
+			str.get_unchecked(0..end_indice) as _
 		}
 	}
 

src/lexer/mod.rs

@@ -100,7 +100,7 @@ impl<'a, 'b> Lexer<'a, 'b> {
 						.map(|v| self.get_token(token::TokenType::Int(v)))
 						.map_err(|_| LexingErrorKind::IntPrimitiveTooBig)
 				};
-				return res.map(|v| Some(v)).map_err(|e| self.get_error(e))
+				return res.map(Some).map_err(|e| self.get_error(e));
 				/*
 
 					Err(IntErrorKind::PosOverflow) | Err(IntErrorKind::NegOverflow) => return Err(self.get_error(LexingErrorKind::IntPrimitiveTooBig)),
@@ -191,7 +191,7 @@ mod tests {
 
 	#[test]
 	fn test_int_literal_too_large() {
-		let mut lexer = Lexer::new("2222222222222222222", None);
+		let mut lexer = Lexer::new("2222222222222222222223", None);
 		let errors = lexer.scan_tokens().unwrap_err();
 		assert_eq!(errors.len(), 1);
 		assert!(matches!(

src/lexer/token.rs

@@ -6,6 +6,12 @@ pub struct Token<'a> {
 	pub location: Location<'a>,
 }
 
+impl<'a> Token<'a> {
+	pub fn as_tuple<'b>(&'b self) -> (&'b TokenType, Location<'a>) {
+		(&self.token_type, self.location)
+	}
+}
+
 #[derive(Debug)]
 pub enum TokenType {
 	LeftParen,

src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(char_indices_offset)]
 pub mod ast;
 pub mod error;
 pub mod interpreter;

tests/integration_test.rs

@@ -2,12 +2,12 @@ use crftng_intrprtrs::run;
 
 #[test]
 fn test_one_equality() {
-	run_check_result_eq_bool("1 == 1", true);
-	run_check_result_eq_bool("1 >= 1", true);
-	run_check_result_eq_bool("1 <= 1", true);
-	run_check_result_eq_bool("1 != 1", false);
-	run_check_result_eq_bool("1 > 1", false);
-	run_check_result_eq_bool("1 < 1", false);
+	run_check_result_eq_bool("1 == 1;", true);
+	run_check_result_eq_bool("1 >= 1;", true);
+	run_check_result_eq_bool("1 <= 1;", true);
+	run_check_result_eq_bool("1 != 1;", false);
+	run_check_result_eq_bool("1 > 1;", false);
+	run_check_result_eq_bool("1 < 1;", false);
 }
 
 fn run_check_result_eq_bool(code: &str, value: bool) {