implement basic control flow, error handling from functions, many tests

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

src/stl/append.rs

@@ -0,0 +1,52 @@
+/* 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};
+
+// Some essential operations below
+pub fn append_callback (ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    // if car is a list, append cdr
+    // otherwise create a list out of all arguments
+    if let Ctr::Seg(ref s) = *ast.car {
+        let mut temp = s.clone();
+        temp.append(ast.cdr.clone());
+        Ok(Ctr::Seg(temp))
+    } else {
+        let mut temp = Seg::new();
+        let mut car_iter = &ast.car;
+        let mut cdr_iter = &ast.cdr;
+        loop {
+            temp.append(car_iter.clone());
+            if let Ctr::Seg(ref s) = **cdr_iter {
+                car_iter = &s.car;
+                cdr_iter = &s.cdr;
+            } else {
+                break;
+            }
+        }
+
+        Ok(Ctr::Seg(temp))
+    }
+}
+
+pub fn expand_callback (ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    if let Ctr::Seg(_) = *ast.car {
+        Ok(*ast.car.clone())
+    } else {
+        Err("non list passed to expand!".to_string())
+    }
+}

src/stl/control.rs

@@ -0,0 +1,62 @@
+/* relish: versatile lisp shell
+ * 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::eval::eval;
+use crate::sym::SymTable;
+
+pub fn if_callback (ast: &Seg, syms: &mut SymTable) -> Result<Ctr, String> {
+    if let Ctr::Seg(ref cond_form) = *ast.car {
+        if let Ctr::Bool(cond) = *eval(cond_form, syms)? {
+            if let Ctr::Seg(ref first_form) = *ast.cdr {
+                if cond {
+                    match *first_form.car {
+                        Ctr::Seg(ref first_arg) => Ok(*eval(first_arg, syms)?),
+                        _ => Ok(*eval(&Seg::from_mono(first_form.car.clone()), syms)?),
+                    }
+                } else {
+                    if let Ctr::Seg(ref second_form) = *first_form.cdr {
+                        match *second_form.car {
+                            Ctr::Seg(ref second_arg) => Ok(*eval(second_arg, syms)?),
+                            _ => Ok(*eval(&Seg::from_mono(second_form.car.clone()), syms)?),
+                        }
+                    } else {
+                        Err("impossible condition: args not in standard form".to_string())
+                    }
+                }
+            } else {
+                Err("impossible condition: not 3 args to if".to_string())
+            }
+        } else {
+            Err("first argument to if must evaluate to be a boolean".to_string())
+        }
+    } else {
+        Err("impossible condition: not 3 args to if".to_string())
+    }
+}
+
+fn let_callback (_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}
+
+fn while_callback (_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}
+
+fn map_callback (_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    todo!()
+}

src/stl/str.rs

@@ -0,0 +1,86 @@
+/* relish: versatile lisp shell
+ * 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::func::{Args, FTable, Function, Operation};
+use crate::segment::{ast_as_string, circuit, Ast, Ctr};
+use crate::vars::VTable;
+use std::cell::RefCell;
+use std::rc::Rc;
+
+// Current primitive is to use a get_NNNNN function defined for each library function which returns a not-previously-owned
+// copy of the Function struct.
+pub fn get_echo() -> Function {
+    return Function {
+        name: String::from("echo"),
+        loose_syms: false,
+        eval_lazy: false,
+        args: Args::Lazy(-1),
+        function: Operation::Internal(Box::new(
+            |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                let mut string = String::from("");
+                if !circuit(a, &mut |arg: &Ctr| {
+                    match arg {
+                        // should be a thing here
+                        Ctr::Symbol(_) => return false,
+                        Ctr::String(s) => string.push_str(&s),
+                        Ctr::Integer(i) => string.push_str(&i.to_string()),
+                        Ctr::Float(f) => string.push_str(&f.to_string()),
+                        Ctr::Bool(b) => string.push_str(&b.to_string()),
+                        Ctr::Seg(c) => string.push_str(ast_as_string(c.clone(), true).as_str()),
+                        Ctr::None => (),
+                    }
+                    println!("{}", string);
+                    return true;
+                }) {
+                    eprintln!("circuit loop in echo should not have returned false")
+                }
+                return Ctr::None;
+            },
+        )),
+    };
+}
+
+pub fn get_concat() -> Function {
+    return Function {
+        name: String::from("concat"),
+        loose_syms: false,
+        eval_lazy: false,
+        args: Args::Lazy(-1),
+        function: Operation::Internal(Box::new(
+            |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                let mut string = String::from("");
+                if !circuit(a, &mut |arg: &Ctr| {
+                    match arg {
+                        // should be a thing here
+                        Ctr::Symbol(_) => return false,
+                        Ctr::String(s) => string.push_str(&s),
+                        Ctr::Integer(i) => string.push_str(&i.to_string()),
+                        Ctr::Float(f) => string.push_str(&f.to_string()),
+                        Ctr::Bool(b) => string.push_str(&b.to_string()),
+                        Ctr::Seg(c) => string.push_str(ast_as_string(c.clone(), true).as_str()),
+                        Ctr::None => (),
+                    }
+                    return true;
+                }) {
+                    eprintln!("circuit loop in concat should not have returned false")
+                }
+                return Ctr::String(string);
+            },
+        )),
+    };
+}
+*/