101 lines
3.0 KiB
Rust
101 lines
3.0 KiB
Rust
use std::{rc::Rc, cell::RefCell};
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use complexpr::{value::{Value, func::Func}, RuntimeError, env::Environment};
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use crate::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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declare_fn!(env, nth, 2);
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declare_fn!(env, last, 1);
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declare_fn!(env, void, 1);
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}
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fn fn_take(args: Vec<Value>) -> Result<Value, RuntimeError> {
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let idx = RefCell::new(0);
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let limit = match args[0] {
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Value::Int(n) => n,
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_ => return Err("Argument to take must be an integer".into()),
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};
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let it = RefCell::new(args[1].iter()?);
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Ok(Value::Func(Func::BuiltinClosure {
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arg_count: 0,
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func: Rc::new(move |_| {
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if *idx.borrow() >= limit {
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Ok(Value::Nil)
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} else {
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*idx.borrow_mut() += 1;
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match it.borrow_mut().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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}))
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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 = RefCell::new(args[1].iter()?);
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let idx = RefCell::new(0);
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Ok(Value::Func(Func::BuiltinClosure {
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arg_count: 0,
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func: Rc::new(move |_| {
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while *idx.borrow() < n {
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it.borrow_mut().next();
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*idx.borrow_mut() += 1;
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}
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match it.borrow_mut().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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}
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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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fn fn_nth(args: Vec<Value>) -> Result<Value, RuntimeError> {
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match &args[0] {
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Value::Int(n) if *n < 0 => Err("First argument to nth must be positive".into()),
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Value::Int(n) => args[1].iter()?.nth(*n as usize).unwrap_or(Ok(Value::Nil)),
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_ => Err("First argument to nth must be an integer".into())
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}
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}
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fn fn_last(args: Vec<Value>) -> Result<Value, RuntimeError> {
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args[0].iter()?.last().unwrap_or(Ok(Value::Nil))
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}
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fn fn_void(args: Vec<Value>) -> Result<Value, RuntimeError> {
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for _ in args[0].iter()? {}
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Ok(Value::Nil)
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}
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