feat: parse array access in an expression

CHANGELOG.md

@@ -2,21 +2,28 @@
 
 ## TODO
 
-- Implement functions as first class citizens
-- Parse __more__ binary operators
-- Parse more complex bindings
-- Namespace identifiers in the symbol table
-- Stdlib
-- Document code
-- Watch mode
-- Simple language server
-- Decide how to handle comments in the syntax (?)(should comments mean something like in rust?)
-- Abstract the parsing of datatypes, such that in the future generics can be implemented in a single place
-- Begin work on the code formatter
-- Remove all panic! and todo!
-- Change REPL to execute code only after `;;` is found
-- Forward the code generated by the REPL to the PHP repl
-- Test assignment parsing
+- [ ] Implement functions as first class citizens
+- [ ] Parse __more__ binary operators
+- [ ] Parse more complex bindings
+- [ ] Namespace identifiers in the symbol table
+- [ ] Stdlib
+- [ ] Document code
+- [ ] Watch mode
+- [ ] Simple language server
+- [ ] Decide how to handle comments in the syntax (?)(should comments mean something like in rust?)
+- [ ] Abstract the parsing of datatypes, such that in the future generics can be implemented in a single place
+- [ ] Begin work on the code formatter
+- [ ] Remove all panic! and todo!
+- [ ] Change REPL to execute code only after `;;` is found
+- [ ] Forward the code generated by the REPL to the PHP repl
+- [ ] Test assignment parsing
+
+
+## v0.1.4
+
+- [ ] Parse obj/map/dict syntax
+- [ ] Parse tuple syntax
+- [ ] Parse class instantiation syntax
 
 
 ## v0.1.3
@@ -25,9 +32,9 @@
 - [ ] Generate php code from current AST
 - [x] Test correct operator precedence
 - [x] Parse assignments
-- [ ] Parse dot `.` operator
+- [x] Parse dot `.` operator
 - [ ] Parse logic operators `&& ||`
-- [ ] Parse Array access `arr[pos]`
+- [x] Parse Array access `arr[pos]`
 - [ ] Parse namespace operator `::`
 - [ ] Implement subtyping for numbers
 

src/error_handling/error_messages.rs

@@ -24,6 +24,7 @@ pub const COMPILER_TODO: u32 = 20;
 pub const SEMANTIC_MISMATCHED_TYPES: u32 = 21;
 pub const SEMANTIC_DUPLICATED_REFERENCE: u32 = 22;
 pub const SEMANTIC_MISMATCHED_ARGUMENT_COUNT: u32 = 23;
+pub const SYNTAX_INVALID_ARRAY_ACCESS: u32 = 24;
 
 /// Reads the error codes from the error code list
 pub fn error_code_to_string() -> String {

src/php_ast/transformers/expression.rs

@@ -45,6 +45,7 @@ impl<'a> PHPTransformable<'a> for Expression<'_> {
                 PExpresssion::BinaryOp(Box::new(left_value), Box::new(right_value), &op.value)
             }
             Expression::Array(_) => unimplemented!("transform array into php"),
+            Expression::ArrayAcccess(_) => unimplemented!("transform array access into php"),
         }
     }
 }

src/semantic/checks/expression/mod.rs

@@ -262,6 +262,7 @@ impl SemanticCheck for Expression<'_> {
 
                 Ok(())
             }
+            Expression::ArrayAcccess(_array_access) => unimplemented!("typecheck array access"),
         }
     }
 }

src/semantic/types/expression.rs

@@ -219,6 +219,7 @@ impl Typed for Expression<'_> {
                 let first_type = arr.exps[0].get_type(scope)?;
                 Ok(Type::Generic("Array".into(), vec![first_type]))
             }
+            Expression::ArrayAcccess(_array_access) => unimplemented!("typecheck array access"),
         }
     }
 }

src/syntax/ast/mod.rs

@@ -121,6 +121,7 @@ pub enum Expression<'a> {
     /// left expression, right expression, operator
     BinaryOperator(Box<Expression<'a>>, Box<Expression<'a>>, &'a Token),
     Array(Array<'a>),
+    ArrayAcccess(ArrayAccess<'a>),
 }
 
 #[derive(Debug)]
@@ -132,6 +133,13 @@ pub struct Array<'a> {
     pub end: usize,
 }
 
+#[derive(Debug)]
+pub struct ArrayAccess<'a> {
+    pub left_expr: Box<Expression<'a>>,
+    pub idx_expr: Box<Expression<'a>>,
+    pub end_pos: usize,
+}
+
 impl Positionable for Expression<'_> {
     /// Returns the absolute start and end position
     /// of this expression
@@ -158,6 +166,10 @@ impl Positionable for Expression<'_> {
                 end,
                 exps: _,
             }) => (*start, *end),
+            Expression::ArrayAcccess(a) => {
+                let (start, _) = a.left_expr.get_position();
+                (start, a.end_pos)
+            }
         }
     }
 }

src/syntax/parsers/expression/function_call_expr.rs

@@ -1,8 +1,11 @@
 use crate::{
-    lexic::token::Token,
+    error_handling::{error_messages::SYNTAX_INVALID_ARRAY_ACCESS, ErrorContainer, ErrorLabel},
+    lexic::token::{Token, TokenType},
     syntax::{
-        ast::{functions::FunctionCall, Expression},
+        ast::{functions::FunctionCall, ArrayAccess, Expression},
         functions::arguments_list,
+        parseable::Parseable,
+        utils::parse_token_type,
         ParsingError, ParsingResult,
     },
 };
@@ -11,6 +14,7 @@ use crate::{
 ///
 /// ```ebnf
 /// function call expr = primary, "(", (arguments list)?, ")"
+///                    | primary, "[", expressions, "]"
 ///                    | primary;
 /// ```
 pub fn try_parse(tokens: &Vec<Token>, pos: usize) -> ParsingResult<Expression> {
@@ -19,21 +23,90 @@ pub fn try_parse(tokens: &Vec<Token>, pos: usize) -> ParsingResult<Expression> {
         _ => return Err(ParsingError::Unmatched),
     };
 
+    // Attempt to parse a function call
     // Parse arguments list
-    let (arguments, next_pos) = match arguments_list::try_parse(tokens, next_pos) {
-        Ok((args, next)) => (args, next),
-        Err(ParsingError::Err(err)) => return Err(ParsingError::Err(err)),
-        _ => {
-            return Ok((primary_expr, next_pos));
+    match arguments_list::try_parse(tokens, next_pos) {
+        Ok((arguments, next_pos)) => {
+            let fun_call = FunctionCall {
+                function: Box::new(primary_expr),
+                arguments: Box::new(arguments),
+            };
+
+            return Ok((Expression::FunctionCall(fun_call), next_pos));
         }
+        Err(ParsingError::Err(err)) => return Err(ParsingError::Err(err)),
+        _ => {}
     };
 
-    let fun_call = FunctionCall {
-        function: Box::new(primary_expr),
-        arguments: Box::new(arguments),
+    // Attempt to parse an array access
+    match try_parse_array_access(tokens, next_pos) {
+        Ok(((array_idx, end_pos), next_pos)) => {
+            let fun_call = ArrayAccess {
+                left_expr: Box::new(primary_expr),
+                idx_expr: Box::new(array_idx),
+                end_pos,
+            };
+
+            return Ok((Expression::ArrayAcccess(fun_call), next_pos));
+        }
+        Err(ParsingError::Err(err)) => return Err(ParsingError::Err(err)),
+        _ => {}
     };
 
-    Ok((Expression::FunctionCall(fun_call), next_pos))
+    // Return the parsed primary
+    return Ok((primary_expr, next_pos));
+}
+
+pub fn try_parse_array_access(
+    tokens: &Vec<Token>,
+    pos: usize,
+) -> ParsingResult<(Expression, usize)> {
+    let (_token, next_pos) = parse_token_type(&tokens, pos, TokenType::LeftBracket)?;
+
+    // parse an expression
+    let (exp, next_pos) = match Expression::try_parse(tokens, next_pos) {
+        Ok(t) => t,
+        Err(ParsingError::Mismatch(e)) => {
+            let label = ErrorLabel {
+                message: String::from("Expected an expression for this array access"),
+                start: e.position,
+                end: e.get_end_position(),
+            };
+            let econtainer = ErrorContainer {
+                error_code: SYNTAX_INVALID_ARRAY_ACCESS,
+                error_offset: e.position,
+                labels: vec![label],
+                note: None,
+                help: None,
+            };
+            return Err(ParsingError::Err(econtainer));
+        }
+        Err(ParsingError::Unmatched) => {
+            //
+            let label = ErrorLabel {
+                message: String::from("Expected an expression for this array access"),
+                start: pos,
+                end: pos + 1,
+            };
+            let econtainer = ErrorContainer {
+                error_code: SYNTAX_INVALID_ARRAY_ACCESS,
+                error_offset: pos,
+                labels: vec![label],
+                note: None,
+                help: None,
+            };
+            return Err(ParsingError::Err(econtainer));
+        }
+        Err(ParsingError::Err(e)) => return Err(ParsingError::Err(e)),
+    };
+
+    // parse the closing bracket
+    let (closed_bracket, next) = match parse_token_type(tokens, next_pos, TokenType::RightBracket) {
+        Ok(t) => t,
+        Err(e) => return Err(e),
+    };
+
+    return Ok(((exp, closed_bracket.get_end_position()), next));
 }
 
 #[cfg(test)]