118 lines
2.8 KiB
Rust
118 lines
2.8 KiB
Rust
use schala_lang::parsing::{AST, Statement, Declaration, Expression, ExpressionType, TypeAnno};
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pub struct ReplState {
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}
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type EvalResult<T> = Result<T, String>;
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enum FullyEvaluatedExpr {
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UnsignedInt(u64),
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SignedInt(i64),
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Float(f64),
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Str(String),
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Bool(bool),
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Other
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}
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impl ReplState {
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pub fn new() -> ReplState {
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ReplState { }
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}
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pub fn evaluate(&mut self, ast: AST) -> Vec<String> {
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let mut acc = vec![];
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for statement in ast.0 {
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match self.eval_statement(statement) {
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Ok(output) => {
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if let Some(s) = output {
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acc.push(s);
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}
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},
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Err(error) => {
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acc.push(format!("Error: {}", error));
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return acc;
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},
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}
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}
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acc
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}
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}
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impl ReplState {
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fn eval_statement(&mut self, statement: Statement) -> EvalResult<Option<String>> {
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use self::FullyEvaluatedExpr::*;
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match statement {
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Statement::ExpressionStatement(expr) => {
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self.eval_expr(expr).map( |eval| {
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match eval {
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UnsignedInt(n) => Some(format!("{}", n)),
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SignedInt(n) => Some(format!("{}", n)),
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Float(f) => Some(format!("{}", f)),
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Str(s) => Some(format!("\"{}\"", s)),
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Bool(b) => Some(format!("{}", b)),
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_ => None,
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}
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})
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},
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Statement::Declaration(decl) => {
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self.eval_decl(decl);
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Ok(None)
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}
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}
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}
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fn eval_decl(&mut self, decl: Declaration) -> EvalResult<()> {
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Err("Not implmemented".to_string())
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}
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fn eval_expr(&mut self, expr: Expression) -> EvalResult<FullyEvaluatedExpr> {
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use self::ExpressionType::*;
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use self::FullyEvaluatedExpr::*;
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let expr_type = expr.0;
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match expr_type {
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IntLiteral(n) => Ok(UnsignedInt(n)),
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FloatLiteral(f) => Ok(Float(f)),
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StringLiteral(s) => Ok(Str(s.to_string())),
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BoolLiteral(b) => Ok(Bool(b)),
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_ => Err(format!("Unimplemented")),
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}
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}
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}
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pub enum TypeCheck {
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OK,
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Error(String)
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}
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impl TypeCheck {
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fn new(msg: &str) -> TypeCheck {
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TypeCheck::Error(msg.to_string())
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}
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}
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impl ReplState {
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pub fn type_check(&mut self, ast: &AST) -> TypeCheck {
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use self::ExpressionType::*;
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for statement in ast.0.iter() {
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match statement {
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&Statement::Declaration(ref decl) => {
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return TypeCheck::new("Declarations not supported");
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},
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&Statement::ExpressionStatement(ref expr) => {
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match (&expr.0, &expr.1) {
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(&IntLiteral(_), &Some(ref t)) => {
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match t {
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&TypeAnno::Singleton { ref name, ref params } if **name == "Int" && params.len() == 0 => (),
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t => return TypeCheck::new(&format!("Bad type {:?} for int literal", t)),
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}
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},
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_ => (),
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}
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}
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}
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}
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TypeCheck::OK
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}
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}
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