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56 lines
3.2 KiB
Rust
56 lines
3.2 KiB
Rust
use crate::env::{arithmetic_op, car, comparison_op, env_new, env_set, mal_exit, Env};
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// This is the first time I implement a macro, and I'm copying it
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// so I will comment this a LOT
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macro_rules! env_init {
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($outer:expr) => {
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// match any istance with no args
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{
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// the macro prevent the macro from disrupting the external code
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// this is the block of code that will substitute the macro
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env_new($outer)
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// returns an empty map
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}
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};
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($outer:expr, $($key:expr => $val:expr),*) => {
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// Only if previous statements did not match,
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// note that the expression with fat arrow is arbitrary,
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// could have been slim arrow, comma or any other
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// recognizable structure
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{
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// create an empty map
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let map = env_init!($outer);
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$( // Do this for all elements of the arguments list
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env_set(&map, $key, &$val);
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)*
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// return the new map
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map
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}
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};
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}
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use crate::printer::prt;
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use crate::types::mal_comp;
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use crate::types::MalType::{Bool, Fun, Int, List, Nil, Str};
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pub fn ns_init() -> Env {
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env_init!(None,
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"test" => Fun(|_| Ok(Str("This is a test function".to_string())), "Just a test function"),
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"exit" => Fun(mal_exit, "Quits the program with specified status"),
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"+" => Fun(|a| arithmetic_op(0, |a, b| a + b, a), "Returns the sum of the arguments"),
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"-" => Fun(|a| arithmetic_op(0, |a, b| a - b, a), "Returns the difference of the arguments"),
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"*" => Fun(|a| arithmetic_op(1, |a, b| a * b, a), "Returns the product of the arguments"),
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"/" => Fun(|a| arithmetic_op(1, |a, b| a / b, a), "Returns the division of the arguments"),
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">" => Fun(|a| comparison_op(|a, b| a > b, a), "Returns true if the arguments are in strictly descending order, 'nil' otherwise"),
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"<" => Fun(|a| comparison_op(|a, b| a > b, a), "Returns true if the arguments are in strictly ascending order, 'nil' otherwise"),
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">=" => Fun(|a| comparison_op(|a, b| a >= b, a), "Returns true if the arguments are in descending order, 'nil' otherwise"),
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"<=" => Fun(|a| comparison_op(|a, b| a <= b, a), "Returns true if the arguments are in ascending order, 'nil' otherwise"),
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"prn" => Fun(|a| { println!("{} ", prt(car(a)?)); Ok(Nil) }, "Print readably all the arguments passed to it"),
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"list" => Fun(|a| Ok(List(a.to_vec())), "Return the arguments as a list"),
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"list?" => Fun(|a| Ok(Bool(matches!(car(a)?, List(_)))), "Return true if the first argument is a list, false otherwise"),
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"empty?" => Fun(|a| Ok(Bool(car(a)?.if_list()?.is_empty())), "Return true if the first parameter is an empty list, false otherwise, returns an error if the element is not a list"),
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"count" => Fun(|a| Ok(Int(car(a)?.if_list()?.len() as isize)), "Return the number of elements in the first argument"),
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"=" => Fun(mal_comp, "Return true if the first two parameters are the same type and content, in case of lists propagate to all elements")
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)
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}
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