88 lines
2.6 KiB
Rust
88 lines
2.6 KiB
Rust
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use std::{rc::Rc, cell::RefCell};
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use crate::{value::{Value, func::{Func, CIterator}}, RuntimeError, env::Environment, declare_fn};
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pub fn load(env: &mut Environment) {
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declare_fn!(env, take, 2);
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declare_fn!(env, skip, 2);
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declare_fn!(env, forall, 2);
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declare_fn!(env, exists, 2);
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}
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fn take_inner(_: Vec<Value>, data: Rc<RefCell<Vec<Value>>>, iter_data: Rc<RefCell<Vec<CIterator>>>) -> Result<Value, RuntimeError> {
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// 0: current index
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// 1: target index
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let mut d = data.borrow_mut();
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if d[0] >= d[1] {
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Ok(Value::Nil)
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} else {
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d[0] = (&d[0] + &Value::Int(1))?;
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match iter_data.borrow_mut()[0].next() {
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None => Ok(Value::Nil),
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Some(x) => x
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}
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}
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}
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fn fn_take(args: Vec<Value>) -> Result<Value, RuntimeError> {
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Ok(Value::Func(Func::BuiltinClosure {
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arg_count: 0,
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data: Rc::new(RefCell::new(vec![Value::Int(0), args[0].clone()])),
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iter_data: Rc::new(RefCell::new(vec![args[1].iter()?])),
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func: take_inner
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}))
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}
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fn skip_inner(_: Vec<Value>, data: Rc<RefCell<Vec<Value>>>, iter_data: Rc<RefCell<Vec<CIterator>>>) -> Result<Value, RuntimeError> {
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let mut d = if let Value::Int(d) = data.borrow()[0] { d } else {
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unreachable!() // checked by fn_skip()
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};
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while d > 0 {
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iter_data.borrow_mut()[0].next();
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d -= 1;
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}
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data.borrow_mut()[0] = Value::Int(d);
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match iter_data.borrow_mut()[0].next() {
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None => Ok(Value::Nil),
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Some(x) => x
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}
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}
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fn fn_skip(args: Vec<Value>) -> Result<Value, RuntimeError> {
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let n = match args[0] {
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Value::Int(n) if n <= 0 => return Err(RuntimeError::new_no_pos("First argument to skip must be nonnegative")),
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Value::Int(n) => n,
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_ => return Err(RuntimeError::new_no_pos("First argument to skip must be an integer"))
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};
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let it = args[1].iter()?;
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Ok(Value::Func(Func::BuiltinClosure {
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arg_count: 0,
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data: Rc::new(RefCell::new(vec![Value::Int(n)])),
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iter_data: Rc::new(RefCell::new(vec![it])),
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func: skip_inner
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}))
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}
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fn fn_forall(args: Vec<Value>) -> Result<Value, RuntimeError> {
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let func = &args[0].as_func()?;
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for item in args[1].iter()? {
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let item = item?;
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if !func.call(vec![item])?.truthy() {
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return Ok(Value::Bool(false))
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}
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}
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Ok(Value::Bool(true))
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}
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fn fn_exists(args: Vec<Value>) -> Result<Value, RuntimeError> {
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let func = &args[0].as_func()?;
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for item in args[1].iter()? {
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let item = item?;
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if func.call(vec![item])?.truthy() {
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return Ok(Value::Bool(true))
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}
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}
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Ok(Value::Bool(false))
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}
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