added expression inference
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f1b8e73703
commit
e625bd4ad2
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@ -0,0 +1,385 @@
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use crate::inference::resolve_call;
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use crate::operators::*;
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use crate::primitives::*;
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use crate::typedef::{GlobalContext, Type, Type::*};
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use rustpython_parser::ast::{
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Comparison, Comprehension, ComprehensionKind, Expression, ExpressionType, Operator,
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UnaryOperator,
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};
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use std::collections::HashMap;
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use std::convert::TryInto;
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use std::rc::Rc;
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type SymTable<'a> = HashMap<&'a str, Rc<Type>>;
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type ParserResult = Result<Option<Rc<Type>>, String>;
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pub fn infer_expr(ctx: &GlobalContext, sym_table: &SymTable, expr: &Expression) -> ParserResult {
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match &expr.node {
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ExpressionType::Number { value } => infer_constant(ctx, sym_table, value),
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ExpressionType::Identifier { name } => infer_identifier(ctx, sym_table, name),
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ExpressionType::List { elements } => infer_list(ctx, sym_table, elements),
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ExpressionType::Tuple { elements } => infer_tuple(ctx, sym_table, elements),
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ExpressionType::Attribute { value, name } => infer_attribute(ctx, sym_table, value, name),
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ExpressionType::BoolOp { values, .. } => infer_bool_ops(ctx, sym_table, values),
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ExpressionType::Binop { a, b, op } => infer_bin_ops(ctx, sym_table, op, a, b),
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ExpressionType::Unop { op, a } => infer_unary_ops(ctx, sym_table, op, a),
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ExpressionType::Compare { vals, ops } => infer_compare(ctx, sym_table, vals, ops),
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ExpressionType::Call {
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args,
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function,
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keywords,
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} => {
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if keywords.len() > 0 {
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Err("keyword is not supported".into())
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} else {
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infer_call(ctx, sym_table, &args, &function)
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}
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}
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ExpressionType::Subscript { a, b } => infer_subscript(ctx, sym_table, a, b),
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ExpressionType::IfExpression { test, body, orelse } => {
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infer_if_expr(ctx, sym_table, &test, &body, orelse)
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}
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ExpressionType::Comprehension { kind, generators } => match kind.as_ref() {
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ComprehensionKind::List { element } => {
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if generators.len() == 1 {
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infer_list_comprehension(ctx, sym_table, element, &generators[0])
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} else {
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Err("only 1 generator statement is supported".into())
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}
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}
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_ => Err("only list comprehension is supported".into()),
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},
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ExpressionType::True | ExpressionType::False => Ok(Some(PrimitiveType(BOOL_TYPE).into())),
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_ => Err("not supported".into()),
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}
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}
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fn infer_constant(
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_: &GlobalContext,
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_: &SymTable,
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value: &rustpython_parser::ast::Number,
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) -> ParserResult {
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use rustpython_parser::ast::Number;
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match value {
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Number::Integer { value } => {
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let int32: Result<i32, _> = value.try_into();
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if int32.is_ok() {
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Ok(Some(PrimitiveType(INT32_TYPE).into()))
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} else {
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let int64: Result<i64, _> = value.try_into();
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if int64.is_ok() {
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Ok(Some(PrimitiveType(INT64_TYPE).into()))
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} else {
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Err("integer out of range".into())
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}
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}
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}
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Number::Float { .. } => Ok(Some(PrimitiveType(FLOAT_TYPE).into())),
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_ => Err("not supported".into()),
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}
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}
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fn infer_identifier(_: &GlobalContext, sym_table: &SymTable, name: &str) -> ParserResult {
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match sym_table.get(name) {
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Some(v) => Ok(Some(v.clone())),
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None => Err("unbounded variable".into()),
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}
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}
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fn infer_list(ctx: &GlobalContext, sym_table: &SymTable, elements: &[Expression]) -> ParserResult {
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if elements.len() == 0 {
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return Ok(Some(ParametricType(LIST_TYPE, vec![BotType.into()]).into()));
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}
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let mut types = elements.iter().map(|v| infer_expr(&ctx, sym_table, v));
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let head = types.next().unwrap()?;
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if head.is_none() {
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return Err("list elements must have some type".into());
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}
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for v in types {
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if v? != head {
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return Err("inhomogeneous list is not allowed".into());
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}
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}
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Ok(Some(ParametricType(LIST_TYPE, vec![head.unwrap()]).into()))
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}
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fn infer_tuple(ctx: &GlobalContext, sym_table: &SymTable, elements: &[Expression]) -> ParserResult {
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let types: Result<Option<Vec<_>>, String> = elements
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.iter()
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.map(|v| infer_expr(&ctx, sym_table, v))
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.collect();
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if let Some(t) = types? {
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Ok(Some(ParametricType(TUPLE_TYPE, t).into()))
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} else {
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Err("tuple elements must have some type".into())
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}
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}
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fn infer_attribute(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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value: &Expression,
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name: &String,
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) -> ParserResult {
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let value = infer_expr(ctx, sym_table, value)?.ok_or("no value".to_string())?;
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if let TypeVariable(id) = value.as_ref() {
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let v = ctx.get_variable(*id);
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if v.bound.len() == 0 {
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return Err("no fields on unbounded type variable".into());
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}
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let ty = v.bound[0]
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.get_base(ctx)
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.and_then(|v| v.fields.get(name.as_str()));
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if ty.is_none() {
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return Err("unknown field".into());
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}
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for x in v.bound[1..].iter() {
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let ty1 = x.get_base(ctx).and_then(|v| v.fields.get(name.as_str()));
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if ty1 != ty {
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return Err("unknown field (type mismatch between variants)".into());
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}
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}
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return Ok(Some(ty.unwrap().clone()));
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}
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match value.get_base(ctx) {
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Some(b) => match b.fields.get(name.as_str()) {
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Some(t) => Ok(Some(t.clone())),
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None => Err("no such field".into()),
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},
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None => Err("this object has no fields".into()),
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}
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}
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fn infer_bool_ops(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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values: &[Expression],
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) -> ParserResult {
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assert_eq!(values.len(), 2);
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let left = infer_expr(ctx, sym_table, &values[0])?.ok_or("no value".to_string())?;
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let right = infer_expr(ctx, sym_table, &values[1])?.ok_or("no value".to_string())?;
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let b = PrimitiveType(BOOL_TYPE);
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if left.as_ref() == &b && right.as_ref() == &b {
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Ok(Some(b.into()))
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} else {
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Err("bool operands must be bool".into())
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}
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}
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fn infer_bin_ops(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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op: &Operator,
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left: &Expression,
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right: &Expression,
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) -> ParserResult {
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let left = infer_expr(ctx, sym_table, left)?.ok_or("no value".to_string())?;
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let right = infer_expr(ctx, sym_table, right)?.ok_or("no value".to_string())?;
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let fun = binop_name(op);
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resolve_call(ctx, Some(left), fun, &[right])
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}
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fn infer_unary_ops(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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op: &UnaryOperator,
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obj: &Expression,
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) -> ParserResult {
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let ty = infer_expr(ctx, sym_table, obj)?.ok_or("no value".to_string())?;
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if let UnaryOperator::Not = op {
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if ty.as_ref() == &PrimitiveType(BOOL_TYPE) {
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Ok(Some(ty))
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} else {
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Err("logical not must be applied to bool".into())
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}
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} else {
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resolve_call(ctx, Some(ty), unaryop_name(op), &[])
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}
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}
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fn infer_compare(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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vals: &[Expression],
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ops: &[Comparison],
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) -> ParserResult {
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let types: Result<Option<Vec<_>>, _> =
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vals.iter().map(|v| infer_expr(ctx, sym_table, v)).collect();
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let types = types?;
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if types.is_none() {
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return Err("comparison operands must have type".into());
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}
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let types = types.unwrap();
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let boolean = PrimitiveType(BOOL_TYPE);
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let left = &types[..types.len() - 1];
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let right = &types[1..];
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for ((a, b), op) in left.iter().zip(right.iter()).zip(ops.iter()) {
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let fun = comparison_name(op).ok_or("unsupported comparison".to_string())?;
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let ty = resolve_call(ctx, Some(a.clone()), fun, &[b.clone()])?;
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if ty.is_none() || ty.unwrap().as_ref() != &boolean {
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return Err("comparison result must be boolean".into());
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}
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}
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Ok(Some(boolean.into()))
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}
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fn infer_call(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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args: &[Expression],
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function: &Expression,
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) -> ParserResult {
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let types: Result<Option<Vec<_>>, _> =
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args.iter().map(|v| infer_expr(ctx, sym_table, v)).collect();
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let types = types?;
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if types.is_none() {
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return Err("function params must have type".into());
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}
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let (obj, fun) = match &function.node {
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ExpressionType::Identifier { name } => (None, name),
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ExpressionType::Attribute { value, name } => (
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Some(infer_expr(ctx, sym_table, &value)?.ok_or("no value".to_string())?),
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name,
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),
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_ => return Err("not supported".into()),
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};
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resolve_call(ctx, obj, fun.as_str(), &types.unwrap())
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}
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fn infer_subscript(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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a: &Expression,
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b: &Expression,
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) -> ParserResult {
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let a = infer_expr(ctx, sym_table, a)?.ok_or("no value".to_string())?;
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let t = if let ParametricType(LIST_TYPE, ls) = a.as_ref() {
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ls[0].clone()
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} else {
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return Err("subscript is not supported for types other than list".into());
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};
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match &b.node {
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ExpressionType::Slice { elements } => {
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let int32 = Rc::new(PrimitiveType(INT32_TYPE));
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let types: Result<Option<Vec<_>>, _> = elements
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.iter()
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.map(|v| {
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if let ExpressionType::None = v.node {
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Ok(Some(int32.clone()))
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} else {
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infer_expr(ctx, sym_table, v)
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}
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})
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.collect();
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let types = types?.ok_or("slice must have type".to_string())?;
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if types.iter().all(|v| v == &int32) {
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Ok(Some(a))
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} else {
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Err("slice must be int32 type".into())
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}
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}
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_ => {
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let b = infer_expr(ctx, sym_table, b)?.ok_or("no value".to_string())?;
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if b.as_ref() == &PrimitiveType(INT32_TYPE) {
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Ok(Some(t))
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} else {
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Err("index must be either slice or int32".into())
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}
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}
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}
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}
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fn infer_if_expr(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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test: &Expression,
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body: &Expression,
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orelse: &Expression,
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) -> ParserResult {
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let test = infer_expr(ctx, sym_table, test)?.ok_or("no value".to_string())?;
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if test.as_ref() != &PrimitiveType(BOOL_TYPE) {
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return Err("test should be bool".into());
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}
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let body = infer_expr(ctx, sym_table, body)?;
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let orelse = infer_expr(ctx, sym_table, orelse)?;
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if body.as_ref() == orelse.as_ref() {
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Ok(body)
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} else {
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Err("divergent type".into())
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}
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}
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fn infer_simple_binding<'a: 'b, 'b>(
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sym_table: &mut SymTable<'b>,
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name: &'a Expression,
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ty: Rc<Type>,
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) -> Result<(), String> {
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match &name.node {
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ExpressionType::Identifier { name } => {
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if name == "_" {
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Ok(())
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} else if sym_table.get(name.as_str()).is_some() {
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Err("duplicated naming".into())
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} else {
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sym_table.insert(name.as_str(), ty);
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Ok(())
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}
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}
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ExpressionType::Tuple { elements } => {
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if let ParametricType(TUPLE_TYPE, ls) = ty.as_ref() {
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if elements.len() == ls.len() {
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for (a, b) in elements.iter().zip(ls.iter()) {
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infer_simple_binding(sym_table, a, b.clone())?;
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}
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Ok(())
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} else {
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Err("different length".into())
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}
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} else {
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Err("not supported".into())
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}
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}
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_ => Err("not supported".into()),
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}
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}
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fn infer_list_comprehension(
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ctx: &GlobalContext,
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sym_table: &SymTable,
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element: &Expression,
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comprehension: &Comprehension,
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) -> ParserResult {
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if comprehension.is_async {
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return Err("async is not supported".into());
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}
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// TODO: it may be more efficient to use multi-level table
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// but it would better done in a whole program level
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let iter = infer_expr(ctx, sym_table, &comprehension.iter)?.ok_or("no value".to_string())?;
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if let ParametricType(LIST_TYPE, ls) = iter.as_ref() {
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let mut local_sym = sym_table.clone();
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infer_simple_binding(&mut local_sym, &comprehension.target, ls[0].clone())?;
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let boolean = PrimitiveType(BOOL_TYPE);
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for test in comprehension.ifs.iter() {
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let result =
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infer_expr(ctx, &local_sym, test)?.ok_or("no value in test".to_string())?;
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if result.as_ref() != &boolean {
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return Err("test must be bool".into());
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}
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}
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let result = infer_expr(ctx, &local_sym, element)?.ok_or("no value")?;
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Ok(Some(ParametricType(LIST_TYPE, vec![result]).into()))
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} else {
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Err("iteration is supported for list only".into())
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}
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}
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@ -2,6 +2,7 @@ extern crate num_bigint;
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extern crate inkwell;
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extern crate rustpython_parser;
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pub mod expression;
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pub mod inference;
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mod operators;
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pub mod primitives;
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