diff options
| -rw-r--r-- | minimal.rs | 56 |
1 files changed, 41 insertions, 15 deletions
@@ -32,23 +32,49 @@ fn is_zero(n: f64) -> bool { /////////////////////////////////// -//let sep = ('(', ')'); -//let ws = (' ', '\t', '\n'); -// TODO: this doesn't handle strings properly. Eg: -// (quote "this ) will ( fail") +fn is_scheme_whitespace(c: char) -> bool{ + " \r\n".find(c) != None +} +fn is_scheme_sep(c: char) -> bool { + "()".find(c) != None +} + +// TODO: need to expand prefix notation stuff like `(1 2 3) to (quote 1 2 3) here? fn scheme_tokenize<'a>(raw_str: &'a str) -> Result<Vec<&'a str>, &'static str> { let mut ret = Vec::<&str>::new(); - for s in raw_str.split_whitespace() { - if s.len() > 1 && s.starts_with('(') { - let (paren, el) = s.split_at(1); - ret.push("("); - ret.push(el); - } else if s.len() > 1 && s.ends_with(')') { - let (el, paren) = s.split_at(s.len() - 1); - ret.push(el); - ret.push(")"); - } else if s.len() > 0 { - ret.push(s); + let mut food: usize = 0; + let mut quoted: bool = false; + for (i, c) in raw_str.chars().enumerate() { + if quoted { + if c == '"' && raw_str.chars().collect::<Vec<char>>()[i-1] != '\\' { + ret.push(&raw_str[i-food-1..i+1]); + quoted = false; + food = 0; + } else if (raw_str.len() == i+1) { + return Err("unmatched quote char"); + } else { + food += 1; + } + } else if c == '"' { + if food > 0 { + return Err("unexpected quote char"); + } + if (raw_str.len() == i+1) { + return Err("unmatched (trailing) quote char"); + } + quoted = true; + } else if is_scheme_whitespace(c) || is_scheme_sep(c) { + if food > 0 { + ret.push(&raw_str[i-food..i]); + } + if is_scheme_sep(c) { + ret.push(&raw_str[i..i+1]); + } + food = 0; + } else if (raw_str.len() == i+1) { + ret.push(&raw_str[i-food..]); + } else { + food += 1; } } return Ok(ret); |