refactor(tazjin/rlox): Unify parser::Statement & parser::Declaration
Change-Id: I6f21b246eb9d3bf760edb3220ce6be5de5b05b08 Reviewed-on: https://cl.tvl.fyi/c/depot/+/2302 Reviewed-by: tazjin <mail@tazj.in> Tested-by: BuildkiteCI
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2 changed files with 20 additions and 27 deletions
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@ -1,5 +1,5 @@
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use crate::errors::{Error, ErrorKind};
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use crate::parser::{self, Declaration, Expr, Literal, Program, Statement};
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use crate::parser::{self, Expr, Literal, Program, Statement};
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use crate::scanner::{self, TokenKind};
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use std::collections::HashMap;
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use std::rc::Rc;
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@ -78,6 +78,14 @@ pub struct Interpreter {
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}
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impl Interpreter {
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pub fn interpret<'a>(&mut self, program: &Program<'a>) -> Result<(), Error> {
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for stmt in program {
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self.interpret_stmt(stmt)?;
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}
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Ok(())
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}
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fn interpret_stmt<'a>(&mut self, stmt: &Statement<'a>) -> Result<(), Error> {
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match stmt {
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Statement::Expr(expr) => {
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@ -87,6 +95,7 @@ impl Interpreter {
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let result = self.eval(expr)?;
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println!("{:?}", result)
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}
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Statement::Var(var) => return self.interpret_var(var),
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}
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Ok(())
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@ -102,17 +111,6 @@ impl Interpreter {
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return Ok(());
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}
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pub fn interpret<'a>(&mut self, program: &Program<'a>) -> Result<(), Error> {
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for decl in program {
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match decl {
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Declaration::Stmt(stmt) => self.interpret_stmt(stmt)?,
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Declaration::Var(var) => self.interpret_var(var)?,
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}
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}
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Ok(())
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}
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fn eval<'a>(&mut self, expr: &Expr<'a>) -> Result<Literal, Error> {
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match expr {
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Expr::Assign(assign) => self.eval_assign(assign),
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@ -54,13 +54,8 @@ pub enum Expr<'a> {
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Variable(Variable<'a>),
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}
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#[derive(Debug)]
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pub enum Statement<'a> {
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Expr(Expr<'a>),
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Print(Expr<'a>),
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}
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// Not to be confused with `Variable`, which is for access.
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// Variable assignment. Not to be confused with `Variable`, which is
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// for access.
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#[derive(Debug)]
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pub struct Var<'a> {
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pub name: Token<'a>,
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@ -68,12 +63,13 @@ pub struct Var<'a> {
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}
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#[derive(Debug)]
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pub enum Declaration<'a> {
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Stmt(Statement<'a>),
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pub enum Statement<'a> {
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Expr(Expr<'a>),
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Print(Expr<'a>),
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Var(Var<'a>),
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}
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pub type Program<'a> = Vec<Declaration<'a>>;
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pub type Program<'a> = Vec<Statement<'a>>;
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// Parser
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@ -109,20 +105,19 @@ struct Parser<'a> {
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type ExprResult<'a> = Result<Expr<'a>, Error>;
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type StmtResult<'a> = Result<Statement<'a>, Error>;
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type DeclResult<'a> = Result<Declaration<'a>, Error>;
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impl<'a> Parser<'a> {
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// recursive-descent parser functions
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fn declaration(&mut self) -> DeclResult<'a> {
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fn declaration(&mut self) -> StmtResult<'a> {
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if self.match_token(&[TokenKind::Var]) {
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return self.var_declaration();
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}
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Ok(Declaration::Stmt(self.statement()?))
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self.statement()
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}
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fn var_declaration(&mut self) -> DeclResult<'a> {
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fn var_declaration(&mut self) -> StmtResult<'a> {
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// Since `TokenKind::Identifier` carries data, we can't use
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// `consume`.
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if let TokenKind::Identifier(_) = self.peek().kind {
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@ -136,7 +131,7 @@ impl<'a> Parser<'a> {
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}
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self.consume(&TokenKind::Semicolon, ErrorKind::ExpectedSemicolon)?;
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return Ok(Declaration::Var(var));
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return Ok(Statement::Var(var));
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}
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return Err(Error {
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