diff options
Diffstat (limited to 'lib/xixanta/src/parser.rs')
| -rw-r--r-- | lib/xixanta/src/parser.rs | 86 |
1 files changed, 67 insertions, 19 deletions
diff --git a/lib/xixanta/src/parser.rs b/lib/xixanta/src/parser.rs index 322bd76..d88a8a2 100644 --- a/lib/xixanta/src/parser.rs +++ b/lib/xixanta/src/parser.rs @@ -159,7 +159,7 @@ impl Parser { // followed by more code. Hence, push it first, then fetch the next // identifier and finally fall through. self.offset = 0; - let (mut id, mut nt) = self.parse_identifier(l)?; + let (mut id, mut nt) = self.parse_identifier(l, true)?; if nt == NodeType::Label { self.nodes.last_mut().unwrap().push(PNode { node_type: nt, @@ -181,7 +181,7 @@ impl Parser { // The label is followed by a statement. Let's parse the identifier // for it and fall through. self.offset = 0; - (id, nt) = self.parse_identifier(l)?; + (id, nt) = self.parse_identifier(l, true)?; if nt == NodeType::Label { return Err(self .parser_error("cannot have multiple labels at the same location") @@ -232,15 +232,16 @@ impl Parser { } } - // Given a `line` parses an identifier if possible. This identifier is not - // necessary an "identifier" per se, but rather a first identifier-like - // string which can be used to determine which kind of expression we are - // dealing with. Returns a PString representing this identifier on success, + // Given a `line` parses an identifier if possible. This identifier can + // optionally allow a '.' character at the first position if `dot` is set to + // true. This is usually a good idea if we can have a label or a control + // statement. Returns a PString representing this identifier on success, // plus a hint on whether the identifier belongs to a label or not. - fn parse_identifier(&mut self, line: &str) -> Result<(PString, NodeType), Error> { + fn parse_identifier(&mut self, line: &str, dot: bool) -> Result<(PString, NodeType), Error> { let start = self.column; let base_offset = self.offset; let mut nt = NodeType::Value; + let mut first_seen = false; // For the general case we just need to iterate until a whitespace // character or an inline comment is found. Then our PString object is @@ -254,6 +255,12 @@ impl Parser { .chars() .peekable(); while let Some(c) = chars.next() { + // Error out if '.' is not allowed from now on. + if c == '.' && (!dot || first_seen) { + return Err(self.parser_error("cannot have a '.' in this context")); + } + first_seen = true; + // Check for the end of the identifier. For this, it's easier to // simply list what is allowed and negate it. if !(c.is_ascii_alphanumeric() || c == '@' || c == '_' || c == '.') { @@ -352,6 +359,9 @@ impl Parser { // The value of the identifier is whatever we have picked up // along the parsing. let value = String::from(line.get(base_offset..self.offset).unwrap_or("").trim()); + if value == "." { + return Err(self.parser_error("empty identifier")); + } // The end of the identifier range has to be shortened for // regular labels because we want to ignore to extra ':' @@ -382,6 +392,9 @@ impl Parser { // The line is merely the identifier (e.g. instruction with implied // addressing). let id = String::from(line.get(base_offset..).unwrap_or_default().trim()); + if id == "." { + return Err(self.parser_error("empty identifier")); + } Ok(( PString { value: id, @@ -550,12 +563,13 @@ impl Parser { // Parse the given `line` as an assignment statement which declares a // variable at `id`. fn parse_assignment(&mut self, line: &str, id: PString) -> Result<(), Error> { - // Notice that `parse_identifier` pretty much swallows any kind of - // identifier without doing any sanity checks. Now it's the time to do - // so. + // Ensure that the parsed identifier is a valid one on assignments. if let Err(msg) = id.is_valid_identifier(false) { return Err(self.parser_error(&msg)); } + if id.value.contains('.') { + return Err(self.parser_error("'.' characters are not allowed for variables")); + } // Skip the '=' sign and any possible whitespaces. self.next(); @@ -1210,7 +1224,7 @@ impl Parser { if first == '(' { self.extract_paren_expression(line, level) } else if first == '.' { - let (id, _) = self.parse_identifier(line)?; + let (id, _) = self.parse_identifier(line, true)?; self.parse_control(id, line, level) } else if first == '\'' { self.parse_char(line) @@ -1248,7 +1262,7 @@ impl Parser { // Like `parse_identifier` but it returns an error if a label was found. fn parse_value(&mut self, line: &str) -> Result<PNode, Error> { - let (id, nt) = self.parse_identifier(line)?; + let (id, nt) = self.parse_identifier(line, true)?; if id.is_empty() { return Err(self.parser_error("invalid identifier")); } @@ -1342,7 +1356,14 @@ impl Parser { let control = match CONTROL_FUNCTIONS.get(&id.value.to_lowercase()) { Some(control) => control, None => { - return Err(self.parser_error(format!("unknown function '{}'", id.value).as_str())) + return Ok(PNode { + node_type: NodeType::Value, + value: id, + left: None, + right: None, + args: None, + source: self.current_source, + }); } }; @@ -1361,7 +1382,7 @@ impl Parser { end: id.end, } } else { - self.parse_identifier(line)?.0 + self.parse_identifier(line, false)?.0 }, left: None, right: None, @@ -1661,6 +1682,25 @@ mod tests { assert_node(nodes.last().unwrap(), NodeType::Instruction, line, "dex") } + #[test] + fn dot_label() { + let line = ".L1: dex"; + + let mut parser = Parser::default(); + assert!(parser.parse(line.as_bytes(), SourceInfo::default()).is_ok()); + + let nodes = parser.nodes(); + assert_eq!(nodes.len(), 2); + + // Label. + assert_eq!(nodes.first().unwrap().value.value, ".L1"); + assert_eq!(nodes.first().unwrap().value.start, 0); + assert_eq!(nodes.first().unwrap().value.end, 3); + + // Instruction + assert_node(nodes.last().unwrap(), NodeType::Instruction, line, "dex") + } + // Literals #[test] @@ -2196,6 +2236,15 @@ mod tests { parser = Parser::default(); err = parser + .parse(".var = 1".as_bytes(), SourceInfo::default()) + .unwrap_err(); + assert_eq!( + err.first().unwrap().message, + "'.' characters are not allowed for variables" + ); + + parser = Parser::default(); + err = parser .parse("var =".as_bytes(), SourceInfo::default()) .unwrap_err(); assert_eq!(err.first().unwrap().message, "incomplete assignment"); @@ -2860,16 +2909,15 @@ inc $20 #[test] fn parse_unknown_control() { let mut parser = Parser::default(); - let mut err = parser + let err = parser .parse(".".as_bytes(), SourceInfo::default()) .unwrap_err(); - assert_eq!(err.first().unwrap().message, "unknown function '.'"); + assert_eq!(err.first().unwrap().message, "empty identifier"); parser = Parser::default(); - err = parser + assert!(parser .parse(".whatever".as_bytes(), SourceInfo::default()) - .unwrap_err(); - assert_eq!(err.first().unwrap().message, "unknown function '.whatever'"); + .is_ok()); } // Macro calls. |