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#[derive(Clone, Debug)]
pub(crate) enum Token {
Comment {
_value: String,
line: usize,
column: usize,
},
BeginDirective {
line: usize,
column: usize,
},
Identifier {
value: String,
line: usize,
column: usize,
},
SoundDividerDirective {
line: usize,
column: usize,
},
Define {
line: usize,
column: usize,
},
}
impl Token {
pub(crate) fn line_column(&self) -> (usize, usize) {
match self {
Token::Comment { line, column, .. }
| Token::BeginDirective { line, column }
| Token::Identifier { line, column, .. }
| Token::Define { line, column, .. }
| Token::SoundDividerDirective { line, column } => (*line, *column),
}
}
}
pub(crate) fn lex(input: &str) -> Vec<Token> {
let mut tokens = Vec::new();
let mut chars = input.chars().peekable();
let mut line = 1;
let mut column = 1;
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
line += 1;
column = 1;
} else {
column += 1;
}
chars.next();
} else if c == '/' {
column += 1;
chars.next();
let Some(&c) = chars.peek() else {
panic!("{line}:{column}: expected '/', found 'EOF'");
};
if c != '/' {
panic!("{line}:{column}: expected '/', found '{c}'");
}
column += 1;
chars.next();
let Some(&c) = chars.peek() else {
tokens.push(Token::Comment {
_value: String::new(),
line,
column,
});
break;
};
column += 1;
chars.next();
// A regular comment.
if c != '#' {
let mut value = String::new();
while let Some(&c) = chars.peek() {
if c == '\n' {
break;
}
value.push(c);
chars.next();
column += 1;
}
tokens.push(Token::Comment {
_value: value,
line,
column,
});
continue;
}
// A directive.
let Some(&c) = chars.peek() else {
panic!("{line}:{column}: expected directive field, found 'EOF'");
};
// Check if the next character is '-' which means we expect the
// sound divider. Note: There is no whitespace allowed between the
// '#' and the first '-'.
if c == '-' {
let mut s = String::new();
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
if s != "-----" {
panic!("{line}:{column}: expected '-----', found '{c}'");
}
break;
}
panic!("{line}:{column}: expected '-----', found '{c}'");
} else if c == '-' {
if s == "-----" {
panic!("{line}:{column}: expected '\n', found '{c}'");
}
s.push(c);
chars.next();
column += 1;
} else {
panic!("{line}:{column}: expected '-----', found '{c}'");
}
}
if s != "-----" {
panic!("{line}:{column}: expected '-----', found 'EOF'");
}
tokens.push(Token::SoundDividerDirective { line, column });
continue;
}
tokens.push(Token::BeginDirective { line, column });
let mut field = String::new();
let mut field_start_column = None;
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
line += 1;
column = 1;
panic!("{line}:{column}: expected directive field, found '\n'");
}
column += 1;
chars.next();
continue;
}
if c == ':' {
if field.is_empty() {
panic!("{line}:{column}: expected directive field, found ':'");
}
column += 1;
chars.next();
break;
}
if field_start_column.is_none() {
field_start_column = Some(column);
}
field.push(c);
chars.next();
column += 1;
}
if field.is_empty() {
panic!("{line}:{column}: expected directive field, found 'EOF'");
}
tokens.push(Token::Identifier {
value: field,
line,
column: field_start_column.unwrap_or(column),
});
let mut value = String::new();
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
break;
}
column += 1;
chars.next();
continue;
}
value.push(c);
chars.next();
column += 1;
}
tokens.push(Token::Identifier {
value,
line,
column,
});
} else if c == '#' {
column += 1;
chars.next();
let mut s = String::new();
let Some(&c) = chars.peek() else {
panic!("{line}:{column}: expected 'define', found 'EOF'");
};
if c.is_alphanumeric() {
while let Some(&c) = chars.peek() {
if c.is_alphanumeric() {
s.push(c);
chars.next();
column += 1;
} else {
break;
}
}
} else {
panic!("{line}:{column}: expected 'define', found '{c}'");
}
if s != "define" {
panic!("{line}:{column}: expected 'define', found 'EOF'");
}
tokens.push(Token::Define { line, column });
let mut sfx_name = String::new();
let mut name_start_column = None;
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
panic!("{line}:{column}: expected name, found '{c}'");
}
column += 1;
chars.next();
} else if c.is_alphanumeric() || c == '_' {
if name_start_column.is_none() {
name_start_column = Some(column);
}
while let Some(&c) = chars.peek() {
if c.is_alphanumeric() || c == '_' {
sfx_name.push(c);
chars.next();
column += 1;
} else {
break;
}
}
break;
} else {
panic!("{line}:{column}: expected name, found '{c}'");
}
}
tokens.push(Token::Identifier {
value: sfx_name,
line,
column: name_start_column.unwrap_or(column),
});
let mut sfx_id = String::new();
let mut id_start_column = None;
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
if c == '\n' {
panic!("{line}:{column}: expected ID, found '{c}'");
}
column += 1;
chars.next();
} else if c.is_ascii_digit() {
if id_start_column.is_none() {
id_start_column = Some(column);
}
while let Some(&c) = chars.peek() {
if c.is_ascii_digit() {
sfx_id.push(c);
chars.next();
column += 1;
} else {
break;
}
}
break;
} else {
panic!("{line}:{column}: expected ID, found '{c}'");
}
}
tokens.push(Token::Identifier {
value: sfx_id,
line,
column: id_start_column.unwrap_or(column),
});
} else {
panic!("{line}:{column}: unexpected '{c}'");
}
}
tokens
}