diff options
Diffstat (limited to 'lib/xixanta')
| -rw-r--r-- | lib/xixanta/src/node.rs | 39 | ||||
| -rw-r--r-- | lib/xixanta/src/parser.rs | 190 |
2 files changed, 217 insertions, 12 deletions
diff --git a/lib/xixanta/src/node.rs b/lib/xixanta/src/node.rs index abc38a1..f6f3d09 100644 --- a/lib/xixanta/src/node.rs +++ b/lib/xixanta/src/node.rs @@ -140,6 +140,25 @@ pub enum ControlType { IncBin, } +/// The type of operation being used. +#[derive(Debug, Clone, PartialEq)] +pub enum OperationType { + Add, + Sub, + Mul, + Div, + Lshift, + Rshift, + And, + Or, + Xor, + UnaryPositive, + UnaryNegative, + BitwiseNot, + LoByte, + HiByte, +} + /// The PNode type. #[derive(Debug, Clone, PartialEq)] pub enum NodeType { @@ -181,6 +200,10 @@ pub enum NodeType { /// A macro call. Note that a Value might also encode this, but when a Call /// has been detected, then there is no doubt on it. Call, + + /// A operation expression. If the operation has two sides, then the left + /// and right arms contain the operands, otherwise only the right one. + Operation(OperationType), } impl fmt::Display for NodeType { @@ -194,6 +217,22 @@ impl fmt::Display for NodeType { NodeType::Literal => write!(f, "literal"), NodeType::Label => write!(f, "label"), NodeType::Call => write!(f, "call"), + NodeType::Operation(op) => match op { + OperationType::Add => write!(f, "addition"), + OperationType::Sub => write!(f, "subtraction"), + OperationType::Mul => write!(f, "multiplication"), + OperationType::Div => write!(f, "division"), + OperationType::Lshift => write!(f, "left shift"), + OperationType::Rshift => write!(f, "right shift"), + OperationType::And => write!(f, "bitwise and"), + OperationType::Or => write!(f, "bitwise or"), + OperationType::Xor => write!(f, "bitwise xor"), + OperationType::UnaryPositive => write!(f, "unary positive"), + OperationType::UnaryNegative => write!(f, "unary negative"), + OperationType::BitwiseNot => write!(f, "bitwise not"), + OperationType::LoByte => write!(f, "low byte"), + OperationType::HiByte => write!(f, "high byte"), + }, } } } diff --git a/lib/xixanta/src/parser.rs b/lib/xixanta/src/parser.rs index d2bb75b..e92f061 100644 --- a/lib/xixanta/src/parser.rs +++ b/lib/xixanta/src/parser.rs @@ -1,5 +1,5 @@ use crate::errors::ParseError; -use crate::node::{NodeType, PNode, PString}; +use crate::node::{NodeType, OperationType, PNode, PString}; use crate::opcodes::{CONTROL_FUNCTIONS, INSTRUCTIONS}; use std::cmp::Ordering; use std::io::{self, BufRead, Read}; @@ -634,9 +634,12 @@ impl Parser { // and the offset has been set accordingly). Returns a new node for the // expression at hand. fn parse_expression(&mut self, line: &str) -> Result<PNode, ParseError> { + // Cases where fetching an "identifier" is really not needed. let first = line.chars().next().unwrap_or_default(); - if first == '(' { + // This is an expression under paranthesis. Get those out of the way + // and call `parse_expression` again but for the expression inside. + // Skip '(' character and whitespace characters in between. self.next(); self.skip_whitespace(line); @@ -648,10 +651,37 @@ impl Parser { // And return what you can parse from the inner expression. self.offset = 0; return self.parse_expression(l); + } else if let Some(node_type) = self.get_unary_from_line(line) { + // This is a unary operation. Just parse the right side and return + // early. + + // Skip operator and whitespaces. + let start = self.column; + self.next(); + self.skip_whitespace(line); + + // Fetch the right side of the operator. + let right_str = line.get(self.offset..).unwrap_or_default().trim_end(); + self.offset = 0; + let right = self.parse_expression(right_str)?; + + return Ok(PNode { + node_type, + value: PString { + value: String::from(""), + line: self.line, + start, + end: right.value.end, + }, + left: None, + right: Some(Box::new(right)), + args: None, + }); } - // There's no complex expression going on. Hence, we can try to parse an - // "identifier" and pass it along. + // Now that we have changed specific cases where detecting an + // "identifier" is not really relevant, let's fetch the "identifier" and + // parse the expression with that into consideration. let (id, nt) = self.parse_identifier(line)?; if nt == NodeType::Label { @@ -661,6 +691,50 @@ impl Parser { } } + // Returns the unary operator type which is at the beginning of the line if + // it exists, otherwise returns None. + fn get_unary_from_line(&mut self, line: &str) -> Option<NodeType> { + match line.chars().nth(0).unwrap_or_default() { + '+' => Some(NodeType::Operation(OperationType::UnaryPositive)), + '-' => Some(NodeType::Operation(OperationType::UnaryNegative)), + '~' => Some(NodeType::Operation(OperationType::BitwiseNot)), + '<' => Some(NodeType::Operation(OperationType::LoByte)), + '>' => Some(NodeType::Operation(OperationType::HiByte)), + _ => None, + } + } + + // Get the operator from the first two characters of the given line. If + // there's no operator, then None is returned for the first element of the + // Ok tuple. Moreover, the second item on the tuple contains the amount of + // characters that made up the operator. + fn get_operation_from_line( + &mut self, + line: &str, + ) -> Result<(Option<NodeType>, usize), ParseError> { + let first = line.chars().nth(0).unwrap_or_default(); + let second = line.chars().nth(1).unwrap_or_default(); + + match first { + '+' => Ok((Some(NodeType::Operation(OperationType::Add)), 1)), + '-' => Ok((Some(NodeType::Operation(OperationType::Sub)), 1)), + '*' => Ok((Some(NodeType::Operation(OperationType::Mul)), 1)), + '/' => Ok((Some(NodeType::Operation(OperationType::Div)), 1)), + '^' => Ok((Some(NodeType::Operation(OperationType::Xor)), 1)), + '|' => Ok((Some(NodeType::Operation(OperationType::Or)), 1)), + '&' => Ok((Some(NodeType::Operation(OperationType::And)), 1)), + '<' => match second { + '<' => Ok((Some(NodeType::Operation(OperationType::Lshift)), 2)), + _ => Err(self.parser_error(format!("unknown operator '<{}'", second).as_str())), + }, + '>' => match second { + '>' => Ok((Some(NodeType::Operation(OperationType::Rshift)), 2)), + _ => Err(self.parser_error(format!("unknown operator '>{}'", second).as_str())), + }, + _ => Ok((None, 0)), + } + } + // Parse the expression under `line` by taking into consideration that a // part of it has already been parsed and evaluated as the given `id`. // Indeces such as `self.column` and `self.offset` are assumed to be correct @@ -684,15 +758,55 @@ impl Parser { } else if line.starts_with('\'') { self.parse_char(id) } else { - // If there is an indication that it might be a macro call, process - // it as such. + // Skip any whitespace after our identifier. self.skip_whitespace(line); - if !line - .get(self.offset..) - .unwrap_or_default() - .trim_end() - .is_empty() - { + let l = line.get(self.offset..).unwrap_or_default().trim_end(); + + // The line might start with a binary operator. This would mean that + // the "id" is actually just the left node of a binary operation and + // that we just need to parse the right arm. + let (op, op_size) = self.get_operation_from_line(l)?; + if let Some(node_type) = op { + // The left node of the operator is simply the "identifier" that + // came to us. + let left = Some(Box::new(PNode { + node_type: NodeType::Value, + value: id.clone(), + left: None, + right: None, + args: None, + })); + + // Fetch a trimmed version of the string that comes after the + // operator. + self.offset += op_size; + self.column += op_size; + self.skip_whitespace(line); + let right_str = line.get(self.offset..).unwrap_or_default().trim_end(); + + // The right node of the operation will be the parsed expression + // of the string we just got right of the operator. + self.offset = 0; + let right = self.parse_expression(right_str)?; + + return Ok(PNode { + node_type, + value: PString { + value: String::from(""), + line: id.line, + start: id.start, + end: right.value.end, + }, + left, + right: Some(Box::new(right)), + args: None, + }); + } + + // Ok, so the line did not indicate any sort of operation. That + // being said, if the rest of the line still contains stuff, it + // might as well be a macro call. Try to process it as such. + if !l.is_empty() { let args = self.parse_arguments(line)?; return Ok(PNode { node_type: NodeType::Call, @@ -1428,6 +1542,58 @@ mod tests { assert_eq!(err.first().unwrap().message, "incomplete assignment"); } + // Constant expressions + + #[test] + fn constant_expression_test() { + let line = "ldx #(4 * NUM_SPRITES)"; + let mut parser = Parser::default(); + assert!(parser.parse(line.as_bytes()).is_ok()); + + let node = parser.nodes.last().unwrap(); + assert_node(node, NodeType::Instruction, line, "ldx"); + assert!(node.args.is_none()); + assert!(node.right.is_none()); + + let literal = &node.left.clone().unwrap(); + assert_node(literal, NodeType::Literal, line, "#"); + + let op = &literal.left.clone().unwrap(); + assert_eq!(op.node_type, NodeType::Operation(OperationType::Mul)); + assert_node(&op.left.clone().unwrap(), NodeType::Value, line, "4"); + assert_node( + &op.right.clone().unwrap(), + NodeType::Value, + line, + "NUM_SPRITES", + ); + } + + #[test] + fn unary_operator_test() { + let line = "ldx #<NUM_SPRITES"; + let mut parser = Parser::default(); + assert!(parser.parse(line.as_bytes()).is_ok()); + + let node = parser.nodes.last().unwrap(); + assert_node(node, NodeType::Instruction, line, "ldx"); + assert!(node.args.is_none()); + assert!(node.right.is_none()); + + let literal = &node.left.clone().unwrap(); + assert_node(literal, NodeType::Literal, line, "#<NUM_SPRITES"); + + let op = &literal.left.clone().unwrap(); + assert_eq!(op.node_type, NodeType::Operation(OperationType::LoByte)); + assert!(op.left.is_none()); + assert_node( + &op.right.clone().unwrap(), + NodeType::Value, + line, + "NUM_SPRITES", + ); + } + // Control statements. #[test] |