add some boolean operations, tests for

Signed-off-by: Ava Hahn <ava@aidanis.online>

src/stl/boolean.rs

@@ -0,0 +1,76 @@
+/* Copyright (C) 2021 Aidan Hahn
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+use crate::segment::{Ctr, Seg};
+use crate::sym::SymTable;
+
+pub fn bool_and_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    let mut type_error = false;
+    let result = ast.circuit(&mut |arg: &Ctr| -> bool {
+        if let Ctr::Bool(b) = *arg {
+            b
+        } else {
+            eprintln!("{} is not a boolean", arg);
+            type_error = true;
+            false
+        }
+    });
+
+    if type_error {
+        Err("all arguments to and must evaluate to boolean".to_string())
+    } else {
+        Ok(Ctr::Bool(result))
+    }
+}
+
+pub fn bool_or_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    let mut result = false;
+    let correct_types = ast.circuit(&mut |arg: &Ctr| -> bool {
+        if let Ctr::Bool(b) = *arg {
+            result = result || b;
+            true
+        } else {
+            eprintln!("{} is not a boolean", arg);
+            false
+        }
+    });
+
+    if !correct_types {
+        Err("all arguments to 'or' must evaluate to boolean".to_string())
+    } else {
+        Ok(Ctr::Bool(result))
+    }
+}
+
+pub fn bool_xor_callback(_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}
+
+pub fn bool_not_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    if let Ctr::Bool(b) = *ast.car {
+        Ok(Ctr::Bool(!b))
+    } else {
+        Err("impossible state: non bool given to not".to_string())
+    }
+}
+
+pub fn bool_iseq_callback(_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}
+
+pub fn bool_toggle_callback(_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}