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64 lines
2.2 KiB
64 lines
2.2 KiB
use super::node_type::*; |
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/// Try to infer types of variables |
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/// |
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/// TODO: Global symbol table is passed around randomly. |
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/// This could probably be cleaned up. |
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pub(super) fn infer(program: &mut Program) -> Result<(), String> { |
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let table = &program.get_symbol_table(); |
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// TODO: Fix aweful nesting |
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for func in &mut program.func { |
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if let Statement::Block(statements, _) = &mut func.body { |
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for statement in statements { |
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match statement { |
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Statement::Declare(var, expr) => { |
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if let None = &var.ty { |
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if let Some(e) = expr { |
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var.ty = infer_expression(&e, table); |
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#[cfg(debug_assertions)] |
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if let None = var.ty { |
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println!("Type of {} could not be infered: {:?}", &var.name, e); |
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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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} |
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} |
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Ok(()) |
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} |
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/// Function table is needed to infer possible function calls |
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fn infer_expression(expr: &Expression, table: &SymbolTable) -> Option<Type> { |
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match expr { |
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Expression::Int(_) => Some(Type::Int), |
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Expression::Bool(_) => Some(Type::Bool), |
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Expression::Str(_) => Some(Type::Str), |
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Expression::FunctionCall(name, _) => infer_function_call(name, table), |
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Expression::Array(els) => infer_array(els, table), |
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_ => None, |
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} |
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} |
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fn infer_array(elements: &Vec<Expression>, table: &SymbolTable) -> Option<Type> { |
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let types: Vec<Option<Type>> = elements |
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.iter() |
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.map(|el| infer_expression(el, table)) |
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.collect(); |
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// TODO: This approach only relies on the first element. |
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// It will not catch that types are possibly inconsistent. |
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match types.first().and_then(|ty| ty.to_owned()) { |
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Some(ty) => Some(Type::Array(Box::new(ty))), |
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None => None, |
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} |
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} |
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fn infer_function_call(name: &str, table: &SymbolTable) -> Option<Type> { |
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match table.get(name) { |
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Some(t) => t.to_owned(), |
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None => None, |
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} |
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}
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