grass/src/builtin/string.rs
2020-02-16 18:32:13 -05:00

96 lines
4.0 KiB
Rust

use std::collections::BTreeMap;
use num_bigint::BigInt;
use num_traits::cast::ToPrimitive;
use num_traits::sign::Signed;
use super::Builtin;
use crate::common::QuoteKind;
use crate::units::Unit;
use crate::value::{Number, Value};
pub(crate) fn register(f: &mut BTreeMap<String, Builtin>) {
decl!(f "to-upper-case", |args, _| {
max_args!(args, 1);
let s: &Value = arg!(args, 0, "string");
match s.eval() {
Value::Ident(i, q) => Ok(Value::Ident(i.to_ascii_uppercase(), q)),
v => Err(format!("$string: {} is not a string.", v).into()),
}
});
decl!(f "to-lower-case", |args, _| {
max_args!(args, 1);
let s: &Value = arg!(args, 0, "string");
match s.eval() {
Value::Ident(i, q) => Ok(Value::Ident(i.to_ascii_lowercase(), q)),
v => Err(format!("$string: {} is not a string.", v).into()),
}
});
decl!(f "str-length", |args, _| {
max_args!(args, 1);
let s: &Value = arg!(args, 0, "string");
match s.eval() {
Value::Ident(i, _) => Ok(Value::Dimension(Number::from(i.len()), Unit::None)),
v => Err(format!("$string: {} is not a string.", v).into()),
}
});
decl!(f "quote", |args, _| {
max_args!(args, 1);
let s = arg!(args, 0, "string").eval();
match s {
Value::Ident(i, _) => Ok(Value::Ident(i, QuoteKind::Double)),
v => Err(format!("$string: {} is not a string.", v).into()),
}
});
decl!(f "unquote", |args, _| {
max_args!(args, 1);
match arg!(args, 0, "string").eval() {
Value::Ident(i, QuoteKind::None) if i.is_empty() => Ok(Value::Null),
i @ Value::Ident(..) => Ok(i.unquote()),
v => Err(format!("$string: {} is not a string.", v).into()),
}
});
decl!(f "str-slice", |args, _| {
max_args!(args, 3);
let (string, quotes) = match arg!(args, 0, "string").eval() {
Value::Ident(s, q) => (s, q),
v => return Err(format!("$string: {} is not a string.", v).into()),
};
let str_len = string.len();
let start = match arg!(args, 1, "start-at").eval() {
Value::Dimension(n, Unit::None) if n.to_integer().is_positive() => n.to_integer().to_usize().unwrap(),
Value::Dimension(n, Unit::None) if n == Number::from(0) => 1_usize,
Value::Dimension(n, Unit::None) if n < -Number::from(str_len) => 1_usize,
Value::Dimension(n, Unit::None) => (BigInt::from(str_len + 1) + n.to_integer()).to_usize().unwrap(),
Value::Dimension(..) => todo!("$start: Expected ___ to have no units."),
_ => todo!("$start-at: ____ is not a number")
};
let mut end = match arg!(args, 2, "end-at"=Value::Null).eval() {
Value::Dimension(n, Unit::None) if n.to_integer().is_positive() => n.to_integer().to_usize().unwrap(),
Value::Dimension(n, Unit::None) if n == Number::from(0) => 0_usize,
Value::Dimension(n, Unit::None) if n < -Number::from(str_len) => 0_usize,
Value::Dimension(n, Unit::None) => (BigInt::from(str_len + 1) + n.to_integer()).to_usize().unwrap(),
Value::Dimension(..) => todo!("$end: Expected ___ to have no units."),
Value::Null => str_len,
_ => todo!("$end-at: ____ is not a number")
};
if end > str_len {
end = str_len;
}
if start > end || start > str_len {
match quotes {
QuoteKind::Double | QuoteKind::Single => Ok(Value::Ident(String::new(), QuoteKind::Double)),
QuoteKind::None => Ok(Value::Null),
}
} else {
let s = string[start-1..end].to_string();
match quotes {
QuoteKind::Double | QuoteKind::Single => Ok(Value::Ident(s, QuoteKind::Double)),
QuoteKind::None => Ok(Value::Ident(s, QuoteKind::None)),
}
}
});
}