Significantly extended stdlib

orchid-std/src/std/boolean.rs

@@ -0,0 +1,47 @@
+use orchid_api_derive::Coding;
+use orchid_base::error::OrcRes;
+use orchid_base::format::FmtUnit;
+use orchid_base::sym;
+use orchid_extension::atom::{Atomic, TAtom};
+use orchid_extension::atom_thin::{ThinAtom, ThinVariant};
+use orchid_extension::conv::{ToExpr, TryFromExpr};
+use orchid_extension::expr::Expr;
+use orchid_extension::gen_expr::{GExpr, sym_ref};
+use orchid_extension::tree::{GenMember, cnst, comments, fun, prefix};
+
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, Coding)]
+pub struct Bool(pub bool);
+impl Atomic for Bool {
+	type Variant = ThinVariant;
+	type Data = Self;
+}
+impl ThinAtom for Bool {
+	async fn print(&self) -> FmtUnit { self.0.to_string().into() }
+}
+impl TryFromExpr for Bool {
+	async fn try_from_expr(expr: Expr) -> OrcRes<Self> {
+		match TAtom::<Bool>::downcast(expr.handle()).await {
+			Err(e) => Err(e.mk_err().await),
+			Ok(atom) => Ok(atom.value),
+		}
+	}
+}
+impl ToExpr for Bool {
+	async fn to_gen(self) -> GExpr {
+		sym_ref(if self.0 { sym!(std::true) } else { sym!(std::false) })
+	}
+}
+
+pub fn gen_bool_lib() -> Vec<GenMember> {
+	prefix("std", [
+		comments(
+			[
+				"Returns the second argument if the bool is true, the third argument otherwise",
+				"|type: Bool -> T -> T -> T|",
+			],
+			fun(true, "ifthenelse", async |Bool(b): Bool, t: Expr, f: Expr| if b { t } else { f }),
+		),
+		cnst(true, "true", Bool(true)),
+		cnst(true, "false", Bool(false)),
+	])
+}