126 lines
3.7 KiB
Rust
126 lines
3.7 KiB
Rust
/* Serene --- Yet an other Lisp
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*
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* Copyright (c) 2020 Sameer Rahmani <lxsameer@gnu.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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use crate::ast::{Callable, Expr, Node, PossibleExpr};
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use crate::errors::err;
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use crate::namespace;
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use crate::reader::read_string;
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use crate::runtime;
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use crate::scope::Scope;
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use crate::types::collections::Seq;
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pub fn string_repr(rt: &runtime::Runtime, expr: &Expr) -> String {
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match expr {
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Expr::Sym(s) => format!(
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"#'{}/{}",
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namespace::get_name(runtime::current_ns(rt)),
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&s.name
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),
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_ => format!("{}", expr),
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}
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}
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pub fn eval_expr(rt: &runtime::Runtime, scope: &Scope, expr: Expr) -> PossibleExpr {
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match &expr {
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// ** Number evaluation
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Expr::Num(_) => Ok(expr),
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// ** Symbol evaluation
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Expr::Sym(s) => {
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if s.is_ns_qualified() {
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return namespace::lookup_external(
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runtime::current_ns(rt),
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&s.target_ns.clone().unwrap(),
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&s.name,
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);
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}
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match scope.lookup(&s.name) {
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Some(e) => Ok(e.expr.clone()),
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_ => Err(err(format!(
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"Undefined binding {} in ns '{}' at {}",
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string_repr(rt, &expr),
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namespace::get_name(runtime::current_ns(rt)),
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s.location()
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))),
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}
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}
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// ** List evaluation
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Expr::Cons(l) => {
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if l.count() == 0 {
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return Ok(Expr::Nil);
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}
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let first = l.first().unwrap();
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let rest = l.rest();
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match eval_expr(rt, scope, first) {
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Ok(e) => match e {
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//Expr::Fn(f) => f.apply(rt, scope, rest),
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Expr::BuiltinFn(b) => Ok(b.apply(rt, scope, rest)),
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_ => Err(err(format!(
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"Can't cast '{}' to functions at {}",
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e.get_type_str(),
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l.location(),
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))),
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},
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Err(e) => Err(e),
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}
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}
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_ => Ok(expr),
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}
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}
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pub fn eval(rt: &runtime::Runtime, scope: &Scope, exprs: Vec<Expr>) -> PossibleExpr {
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if exprs.len() == 0 {
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return Ok(Expr::NoMatch);
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}
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let mut ret: PossibleExpr = Ok(Expr::NoMatch);
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for expr in exprs.iter() {
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ret = eval_expr(rt, scope, expr.clone());
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}
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ret
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}
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pub fn read_eval_print(rt: &runtime::Runtime, input: &str) {
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match read_string(input) {
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Ok(exprs) => {
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if runtime::is_debug(rt) {
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println!("Read Result: \n{:?}\n", exprs);
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}
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let result_expr = eval(
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rt,
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namespace::get_root_scope(&runtime::current_ns(rt)),
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exprs,
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);
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if runtime::is_debug(rt) {
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println!("Eval Result: \n{:?}\n", result_expr);
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}
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match result_expr {
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Ok(expr) => println!("{}", string_repr(rt, &expr)),
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Err(e) => println!("{}", e),
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}
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}
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Err(e) => println!("Error: {}", e),
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}
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}
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