big progress on rewrite

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

the_rewrite/src/eval.rs

@@ -0,0 +1,139 @@
+/* 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::FTable;
+use crate::segment::{Seg, Ctr};
+use crate::vars::VTable;
+
+/* iterates over a syntax tree
+ * returns a NEW LIST of values
+ * representing the simplest possible form of the input
+ */
+pub fn eval<'a>(
+    ast: &'a Seg<'a>,
+    vars: &'a mut VTable<'a>,
+    funcs: &'a mut FTable<'a>,
+    sym_loose: bool,
+) -> Result<Box<Ctr<'a>>, String> {
+    let mut ret = Box::new(Ctr::Seg(Seg::new()));
+    let mut iter: &mut Seg;
+    if let Ctr::Seg(ref mut s) = *ret {
+        iter = s;
+    } else {
+        return Err("Critfail: no fuckin clue whats up here".to_string())
+    }
+
+    let mut car = &ast.car;
+
+    // doing an initial variable check here allows us
+    // to find functions passed in as variables
+    if let Ctr::Symbol(tok) = **car {
+        if let Some(val) = vars.get(tok.clone()) {
+            car = &(val.clone());
+        }
+    }
+
+    // another check to detect if we may have a function call
+    if let Ctr::Symbol(ref tok) = **car {
+        match *ast.cdr {
+            Ctr::Seg(ref ast) => {
+                if let Some(func) = funcs.get(tok.clone()) {
+                    return func.func_call(ast, vars, funcs);
+                } else if !sym_loose {
+                    return Err(format!("Couldnt find definition of {}.", tok));
+                }
+            }
+            Ctr::None => {
+                if let Some(func) = funcs.get(tok.clone()) {
+                    return func.func_call(&Seg::new(), vars, funcs);
+                } else if !sym_loose {
+                    return Err(format!("Couldnt find definition of {}.", tok.clone()));
+                }
+            }
+            _ => return Err(format!("Arguments to function not a list!")),
+        }
+    }
+
+    let mut none = false;
+    while !none {
+        match **car {
+            // if LIST: call eval inner on it with first_item=true
+            Ctr::Seg(ref inner) => {
+                match eval(inner, vars, funcs, sym_loose) {
+                    Ok(res) => (*iter).car = res,
+                    Err(e) => return Err(format!("Evaluation error: {}", e)),
+                }
+            }
+
+            // if SYMBOL: unwrap naively
+            Ctr::Symbol(ref tok) => {
+                if let Some(val) = vars.get(tok.clone()) {
+                    iter.car = val.clone();
+                } else if sym_loose {
+                    iter.car = car.clone()
+                } else {
+                    return Err(format!("Undefined variable: {}", tok.clone()));
+                }
+            }
+
+            // if OTHER: clone and set
+            _ => {
+                iter.car = car.clone();
+            }
+        }
+
+        match *ast.cdr {
+            // if SYMBOL: unwrap naively, then end
+            Ctr::Symbol(ref tok) => {
+                if let Some(val) = vars.get(tok.clone()) {
+                    iter.cdr = val.clone();
+                } else if sym_loose {
+                    iter.cdr = ast.cdr.clone()
+                } else {
+                    return Err(format!("Undefined variable: {}", tok.clone()));
+                }
+
+                none = true;
+            }
+
+            // if LIST:
+            //    - iter.cdr = new_ast(None, None)
+            //    - iter = iter.cdr
+            //    - car = cdr.car
+            //    - cdr = cdr.cdr
+            //    - LOOP
+            Ctr::Seg(next) => {
+                iter.cdr = Box::new(Ctr::Seg(Seg::new()));
+                ast = &next;
+            }
+
+            // if OTHER: clone and set, and then end
+            _ => {
+                iter.cdr = ast.cdr.clone();
+                none = true;
+            }
+        }
+
+        if let Ctr::None = **car {
+            if let Ctr::None = *ast.cdr {
+                none = true;
+            }
+        }
+    }
+
+    return Ok(ret);
+}

the_rewrite/src/func.rs

@@ -0,0 +1,233 @@
+/* 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::eval::eval;
+use crate::segment::{Seg, Ctr, Type};
+use crate::vars::VTable;
+use std::collections::HashMap;
+use std::convert::TryInto;
+
+pub struct FTable<'a>(HashMap<String, Box<Function<'a>>>);
+
+impl<'a> FTable<'a> {
+    pub fn declare(&mut self, func: Box<Function<'a>>) -> Option<String> {
+        if let Operation::External(ref fun) = &func.function {
+            if let Args::Lazy(ref i) = func.args {
+                if fun.arg_syms.len() != i.clone().try_into().unwrap() {
+                    return Some(
+                        "external function must have lazy args equal to declared arg_syms length"
+                            .to_string(),
+                    );
+                }
+            } else {
+                return Some("external function must have lazy args".to_string());
+            }
+        }
+
+        self.0.insert(func.name, func);
+        None
+    }
+
+    pub fn get(&self, id: String) -> Option<&Box<Function<'a>>> {
+        self.0.get(&id)
+    }
+
+    pub fn remove(&self, id: String) {
+        self.0.remove(&id);
+    }
+}
+
+
+// Standardized function signature for stdlib functions
+//pub type InternalOperation = impl Fn(Box<Seg>, Box<VTable>, Box<FTable>) -> Box<Ctr>;
+
+#[derive(Debug)]
+pub struct ExternalOperation<'a> {
+    // Un-evaluated abstract syntax tree
+    // TODO: Intermediate evaluation to simplify branches with no argument in them
+    //       Simplified branches must not have side effects.
+    // TODO: Apply Memoization?
+    pub ast: Box<Seg<'a>>,
+    // list of argument string tokens
+    pub arg_syms: Vec<String>,
+}
+
+/* A stored function may either be a pointer to a function
+ * or a syntax tree to eval with the arguments
+ */
+pub enum Operation<'a> {
+    Internal(Box<dyn for<'b> Fn(&'b Seg, &'b mut VTable, &'b mut FTable) -> Ctr<'b>>),
+    External(ExternalOperation<'a>),
+}
+
+/* Function Args
+ * If Lazy, is an integer denoting number of args
+ * If Strict, is a list of type tags denoting argument type.
+ */
+pub enum Args {
+    // signed: -1 denotes infinite args
+    Lazy(i128),
+    Strict(Vec<Type>),
+}
+
+// function which does not need args checked
+pub struct Function<'a> {
+    pub function: Operation<'a>,
+    pub name: String,
+    pub args: Args,
+
+    // dont fail on undefined symbol (passed to eval)
+    pub loose_syms: bool,
+
+    // dont evaluate args at all. leave that to the function
+    pub eval_lazy: bool,
+}
+
+impl<'a> Function<'a> {
+    /* call
+     * routine is called by eval when a function call is detected
+     */
+    pub fn func_call(
+        &self,
+        args: &'a Seg<'a>,
+        vars: &'a mut VTable<'a>,
+        funcs: &'a mut FTable<'a>,
+    ) -> Result<Box<Ctr<'a>>, String> {
+        let mut evaluated_args = args;
+        if !self.eval_lazy {
+            match eval(args, vars, funcs, self.loose_syms) {
+                Ok(arg_data) => {
+                    if let Ctr::Seg(ast) = *arg_data {
+                        evaluated_args = &ast;
+                    } else {
+                        return Err("Panicking: eval returned not a list for function args.".to_string());
+                    }
+                }
+                Err(s) => {
+                    return Err(format!(
+                        "error evaluating args to {}: {}",
+                        self.name, s
+                    ))
+                }
+            }
+        }
+
+        match self.args {
+            Args::Lazy(ref num) => {
+                let called_arg_count = evaluated_args.len() as i128;
+                if *num == 0 {
+                    if let Ctr::None = *evaluated_args.car {
+                        //pass
+                    } else {
+                        return Err(format!(
+                            "expected 0 args in call to {}. Got one or more.",
+                            self.name,
+                        ));
+                    }
+                } else if *num > -1 && (*num != called_arg_count) {
+                    return Err(format!(
+                        "expected {} args in call to {}. Got {}.",
+                        num, self.name, called_arg_count
+                    ));
+                }
+            }
+
+            Args::Strict(ref arg_types) => {
+                let mut idx: usize = 0;
+                let passes = evaluated_args.circuit(&mut |c: &Ctr| -> bool {
+                    if idx >= arg_types.len() {
+                        return false;
+                    }
+
+                    if let Ctr::None = c {
+                        return false;
+                    }
+
+                    if arg_types[idx] == c.to_type() {
+                        idx += 1;
+                        return true;
+                    }
+                    return false;
+                });
+
+                if passes && idx < (arg_types.len() - 1) {
+                    return Err(format!(
+                        "{} too little arguments in call to {}",
+                        arg_types.len() - (idx + 1),
+                        self.name
+                    ));
+                }
+
+                if !passes {
+                    if idx < (arg_types.len() - 1) {
+                        return Err(format!(
+                            "argument {} in call to {} is of wrong type (expected {})",
+                            idx + 1,
+                            self.name,
+                            arg_types[idx].to_string()
+                        ));
+                    }
+
+                    if idx == (arg_types.len() - 1) {
+                        return Err(format!(
+                            "too many arguments in call to {}",
+                            self.name
+                        ));
+                    }
+                }
+            }
+        }
+
+        /* corecursive with eval.
+         * essentially calls eval on each body in the function.
+         * result of the final body is returned.
+         */
+        match &self.function {
+            Operation::Internal(ref f) => return Ok(Box::new(f(evaluated_args, vars, funcs))),
+            Operation::External(ref f) => {
+                for n in 0..f.arg_syms.len() {
+                    let iter_arg = evaluated_args[n];
+                    vars.insert(f.arg_syms[n].clone(), Box::new(iter_arg));
+                }
+
+                let mut result: Box<Ctr>;
+                let iterate = &*(f.ast);
+                loop {
+                    if let Ctr::Seg(ref data) = *iterate.car {
+                        match eval(data, vars, funcs, self.loose_syms) {
+                            Ok(ctr) => result = ctr,
+                            Err(e) => return Err(e),
+                        }
+                    } else {
+                        panic!("function body not in standard form!")
+                    }
+
+                    match *iterate.cdr {
+                        Ctr::Seg(ref next) => iterate = next,
+                        Ctr::None => break,
+                        _ => panic!("function body not in standard form!"),
+                    }
+                }
+                for n in 0..f.arg_syms.len() {
+                    vars.remove(f.arg_syms[n]);
+                }
+
+                return Ok(result);
+            }
+        }
+    }
+}

the_rewrite/src/lib.rs

@@ -20,26 +20,21 @@
 
 /*mod append;
 mod config;
+ */
 mod eval;
-mod func;*/
+mod func;
 mod lex;
 mod segment;
+mod vars;
 /*mod stl;
-mod str;
-mod vars;*/
+mod str;*/
 
 pub mod ast {
-//    pub use crate::eval::eval;
-//    pub use crate::func::{
-//        func_call, func_declare, Args, ExternalOperation, FTable, Function, Operation,
-//    };
+    pub use crate::eval::eval;
+    pub use crate::func::{Args, ExternalOperation, FTable, Function, Operation};
     pub use crate::lex::lex;
     pub use crate::segment::{Ctr, Seg, Type};
-//    pub use crate::vars::{define, VTable};
-}
-
-mod test {
-
+    pub use crate::vars::VTable;
 }
 
 /*pub mod stdlib {

the_rewrite/src/segment.rs

@@ -16,6 +16,7 @@
  */
 use std::fmt;
 use std::marker::PhantomData;
+use std::ops::Index;
 
 // Container
 #[derive(Debug, Default)]
@@ -68,6 +69,8 @@ pub struct Seg<'a> {
     _lifetime_variance_determinant: PhantomData<&'a ()>
 }
 
+static NOTHING: Ctr = Ctr::None;
+
 impl Ctr<'_> {
     pub fn to_type(&self) -> Type {
         match self {
@@ -84,48 +87,6 @@ impl Ctr<'_> {
 }
 
 impl<'a> Seg<'a> {
-    pub fn new() -> Seg<'a> {
-        return Seg{
-            car: Box::new(Ctr::None),
-            cdr: Box::new(Ctr::None),
-            _lifetime_variance_determinant: PhantomData,
-        }
-    }
-
-    pub fn from(arg: Box<Ctr<'a>>) -> Seg<'a> {
-        return Seg{
-            car: arg,
-            cdr: Box::new(Ctr::None),
-            _lifetime_variance_determinant: PhantomData,
-        }
-    }
-
-    /* applies a function across a list in standard form
-     * function must take a Ctr and return a bool
-     * short circuits on the first false returned.
-     * also returns false on a non standard form list
-     */
-    pub fn circuit<F: FnMut(&Ctr) -> bool>(&self, func: &mut F) -> bool {
-        if func(&self.car) {
-            match &*(self.cdr) {
-                Ctr::None => true,
-                Ctr::Seg(l) => l.circuit(func),
-                _ => false,
-            }
-        } else {
-            false
-        }
-    }
-
-    /* recurs over ast assumed to be list in standard form
-     * returns length
-     */
-    pub fn len(&self) -> u128 {
-        let mut len = 0;
-        self.circuit(&mut |_c: &Ctr| -> bool { len += 1; true });
-        len
-    }
-
     /* recurs over tree assumed to be list in standard form
      * appends object to end of list
      *
@@ -148,6 +109,48 @@ impl<'a> Seg<'a> {
             // pray for memory lost to the void
         }
     }
+
+    /* applies a function across a list in standard form
+     * function must take a Ctr and return a bool
+     * short circuits on the first false returned.
+     * also returns false on a non standard form list
+     */
+    pub fn circuit<F: FnMut(&Ctr) -> bool>(&self, func: &mut F) -> bool {
+        if func(&self.car) {
+            match &*(self.cdr) {
+                Ctr::None => true,
+                Ctr::Seg(l) => l.circuit(func),
+                _ => false,
+            }
+        } else {
+            false
+        }
+    }
+
+    pub fn from(arg: Box<Ctr<'a>>) -> Seg<'a> {
+        return Seg{
+            car: arg,
+            cdr: Box::new(Ctr::None),
+            _lifetime_variance_determinant: PhantomData,
+        }
+    }
+
+    /* recurs over ast assumed to be list in standard form
+     * returns length
+     */
+    pub fn len(&self) -> u128 {
+        let mut len = 0;
+        self.circuit(&mut |_c: &Ctr| -> bool { len += 1; true });
+        len
+    }
+
+    pub fn new() -> Seg<'a> {
+        return Seg{
+            car: Box::new(Ctr::None),
+            cdr: Box::new(Ctr::None),
+            _lifetime_variance_determinant: PhantomData,
+        }
+    }
 }
 
 fn seg_to_string(s: &Seg, parens: bool) -> String {
@@ -178,6 +181,22 @@ impl<'a> Clone for Seg<'a> {
     }
 }
 
+impl<'a> Index<usize> for Seg<'a> {
+    type Output = Ctr<'a>;
+
+    fn index(&self, idx: usize) -> &Self::Output {
+        if idx == 0 {
+            return &self.car;
+        }
+
+        if let Ctr::Seg(ref s) = *self.cdr {
+            return s.index(idx - 1)
+        }
+
+        return &NOTHING;
+    }
+}
+
 impl<'a> Clone for Ctr<'a> {
     fn clone(&self) -> Ctr<'a> {
         match self {

the_rewrite/src/vars.rs

@@ -0,0 +1,85 @@
+/* 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::eval::eval;
+use crate::func::{Args, FTable, Function, Operation};
+use crate::segment::{Seg, Ctr};
+use std::collections::HashMap;
+use std::env;
+/* Mapping between a string token and a tree of Segments
+ * The string token can be found in any Ctr::Symbol value
+ * it is expected that the trees stored are already evaluated
+ */
+pub struct VTable<'a>(HashMap<String, Box<Ctr<'a>>>);
+
+impl<'a> VTable<'a> {
+    // WARNING: make sure var_tree is properly evaluated before storing
+    pub fn insert(&'a mut self, identifier: String, data: Box<Ctr<'a>>) {
+        if let Some(datum) = self.0.insert(identifier, data) {
+            drop(datum);
+        }
+    }
+
+    pub fn get(&'a self, id: String) -> Option<Box<Ctr<'a>>> {
+        return self.0.get(&id);
+    }
+
+    pub fn remove(&self, id: String) {
+        self.0.remove(&id);
+    }
+}
+
+// returns a callback for the stdlib var export function with env_sync on or off
+pub fn get_export<'a> (env_cfg: bool) -> Function<'a> {
+    return Function {
+        name: String::from("export"),
+        loose_syms: true,
+        eval_lazy: true,
+        args: Args::Lazy(2),
+        function: Operation::Internal(Box::new(
+            |ast: &Seg, vars: &mut VTable, funcs: &mut FTable| -> Ctr {
+                if let Ctr::Symbol(identifier) = *ast.car {
+                    match *ast.cdr {
+                        Ctr::Seg(ref data_tree) => match eval(&Box::new(data_tree), vars, funcs, false) {
+                            Ok(seg) => match *seg {
+                                Ctr::Seg(val) => {
+                                    vars.insert(identifier, val.car);
+                                    if env_cfg {
+                                        env::set_var(identifier, val.car.to_string())
+                                    }
+                                },
+                                _ =>  eprintln!("impossible args to export"),
+                            },
+                            Err(e) =>  eprintln!("couldnt eval symbol: {}", e),
+                        },
+                        Ctr::None => {
+                            vars.remove(identifier);
+                            if env_cfg {
+                                env::remove_var(identifier);
+                            }
+                        },
+                        _ =>  eprintln!("args not in standard form"),
+                    }
+                } else {
+                    eprintln!("first argument to export must be a symbol");
+                }
+                return Ctr::None;
+            },
+        )),
+    };
+}
+

the_rewrite/tests/test_eval.rs

@@ -0,0 +1,245 @@
+mod eval_tests {
+    use relish::ast::{ast_to_string, eval, lex, new_ast, FTable, VTable};
+    use relish::ast::{func_declare, Args};
+    use relish::ast::{Ctr, ExternalOperation, Function, Operation};
+    use std::cell::RefCell;
+    use std::rc::Rc;
+
+    // TODO: write generalized testing routine on top of list of inputs
+
+    #[test]
+    fn eval_singlet() {
+        let test_doc = "(1)".to_string();
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+
+        match lex(test_doc.clone()) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            }
+
+            Ok(initial_ast) => match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                Err(e) => {
+                    println!("Evaluation error: {}\n", e);
+                    assert!(false)
+                }
+
+                Ok(reduced) => {
+                    if let Ctr::Seg(reduced_ast) = reduced {
+                        assert_eq!(ast_to_string(reduced_ast), test_doc)
+                    }
+                }
+            },
+        }
+    }
+
+    #[test]
+    fn eval_embedded_lists_no_funcs() {
+        let test_doc = "(1 (1 2 3 4 5) 5)".to_string();
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+
+        match lex(test_doc.clone()) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            }
+
+            Ok(initial_ast) => match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                Err(e) => {
+                    println!("Evaluation error: {}\n", e);
+                    assert!(false)
+                }
+
+                Ok(reduced) => {
+                    if let Ctr::Seg(reduced_ast) = reduced {
+                        assert_eq!(ast_to_string(reduced_ast), test_doc)
+                    }
+                }
+            },
+        }
+    }
+
+    #[test]
+    fn eval_function_call() {
+        let test_doc = "('one' (echo 'unwrap_me'))".to_string();
+        let output = "('one' 'unwrap_me')";
+        let test_external_func: Function = Function {
+            name: String::from("echo"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Lazy(1),
+            function: Operation::External(ExternalOperation {
+                arg_syms: vec!["input".to_string()],
+                ast: new_ast(
+                    Ctr::Seg(new_ast(Ctr::Symbol("input".to_string()), Ctr::None)),
+                    Ctr::None,
+                ),
+            }),
+        };
+
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+        if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(test_external_func))) {
+            print!("Error declaring external func: {}", s);
+            assert!(false);
+        }
+
+        match lex(test_doc) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            }
+
+            Ok(initial_ast) => match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                Err(e) => {
+                    println!("Evaluation error: {}\n", e);
+                    assert!(false)
+                }
+
+                Ok(reduced) => {
+                    if let Ctr::Seg(reduced_ast) = reduced {
+                        let out_doc = ast_to_string(reduced_ast);
+                        if out_doc != output {
+                            print!("Erroneous output: {}\n", out_doc);
+                            assert!(false)
+                        }
+                    }
+                }
+            },
+        }
+    }
+
+    #[test]
+    fn eval_embedded_func_calls() {
+        let test_doc = "('one' (echo (echo 'unwrap_me')))".to_string();
+        let output = "('one' 'unwrap_me')";
+        let test_external_func: Function = Function {
+            name: String::from("echo"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Lazy(1),
+            function: Operation::External(ExternalOperation {
+                arg_syms: vec!["input".to_string()],
+                ast: new_ast(
+                    Ctr::Seg(new_ast(Ctr::Symbol("input".to_string()), Ctr::None)),
+                    Ctr::None,
+                ),
+            }),
+        };
+
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+        if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(test_external_func))) {
+            print!("Error declaring external func: {}", s);
+            assert!(false);
+        }
+
+        match lex(test_doc) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            }
+
+            Ok(initial_ast) => match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                Err(e) => {
+                    println!("Evaluation error: {}\n", e);
+                    assert!(false)
+                }
+
+                Ok(reduced) => {
+                    if let Ctr::Seg(reduced_ast) = reduced {
+                        let out_doc = ast_to_string(reduced_ast);
+                        if out_doc != output {
+                            print!("Erroneous output: {}\n", out_doc);
+                            assert!(false)
+                        }
+                    }
+                }
+            },
+        }
+    }
+
+    /*
+    #[test]
+    fn eval_bad_vars() {
+        let test_doc = "".to_string();
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+
+        match lex(test_doc) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            },
+
+            Ok(initial_ast) => {
+                match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                    Err(e) => {
+                        println!("Evaluation error: {}\n", e);
+                        assert!(false)
+                    },
+
+                    Ok(reduced_ast) => {
+                        // write tests here
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn eval_bad_func() {
+        let test_doc = "".to_string();
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+
+        match lex(test_doc) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            },
+
+            Ok(initial_ast) => {
+                match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                    Err(e) => {
+                        println!("Evaluation error: {}\n", e);
+                        assert!(false)
+                    },
+
+                    Ok(reduced_ast) => {
+                        // write tests here
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn eval_verify_all_elems_cloned() {
+        let test_doc = "".to_string();
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+
+        match lex(test_doc) {
+            Err(e) => {
+                println!("Lexing error: {}\n", e);
+                assert!(false)
+            },
+
+            Ok(initial_ast) => {
+                match eval(initial_ast.clone(), vt.clone(), ft.clone(), false) {
+                    Err(e) => {
+                        println!("Evaluation error: {}\n", e);
+                        assert!(false)
+                    },
+
+                    Ok(reduced_ast) => {
+                        // write tests here
+                    }
+                }
+            }
+        }
+    }*/
+}

the_rewrite/tests/test_func.rs

@@ -0,0 +1,356 @@
+mod func_tests {
+    use relish::ast::VTable;
+    use relish::ast::{
+        func_call, func_declare, lex, Args, ExternalOperation, FTable, Function, Operation,
+    };
+    use relish::ast::{new_ast, Ast, Ctr, Type};
+    use std::cell::RefCell;
+    use std::rc::Rc;
+
+    #[test]
+    fn decl_and_call_internal_func() {
+        let test_internal_func: Function = Function {
+            name: String::from("test_func_in"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Strict(vec![Type::Bool]),
+            function: Operation::Internal(Box::new(
+                |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                    let inner = a.borrow();
+                    let mut is_bool = false;
+                    if let Ctr::Bool(_) = &inner.car {
+                        is_bool = true;
+                    }
+
+                    Ctr::Bool(is_bool)
+                },
+            )),
+        };
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+        let args = new_ast(Ctr::Bool(true), Ctr::None);
+        if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(test_internal_func))) {
+            print!("Error declaring internal func: {}", s);
+            assert!(false);
+        }
+
+        let func: Rc<RefCell<Function>>;
+        if let Some(f) = ft.borrow().get(&"test_func_in".to_string()) {
+            func = f.clone();
+        } else {
+            print!("failed to retrieve function!");
+            assert!(false);
+            return;
+        }
+
+        if let Ok(ret) = func_call(func, args, vt, ft) {
+            match ret {
+                Ctr::Bool(b) => assert!(b),
+                _ => {
+                    print!("invalid return from func!");
+                    assert!(false);
+                }
+            }
+        } else {
+            print!("call to function failed!");
+            assert!(false);
+        }
+    }
+
+    #[test]
+    fn decl_and_call_external_func_singlet() {
+        match lex("((input))".to_string()) {
+            Err(e) => panic!("{}", e),
+            Ok(finner) => {
+                let test_external_func: Function = Function {
+                    name: String::from("echo"),
+                    loose_syms: false,
+                    eval_lazy: false,
+                    args: Args::Lazy(1),
+                    function: Operation::External(ExternalOperation {
+                        arg_syms: vec!["input".to_string()],
+                        ast: finner,
+                    }),
+                };
+                let ft = Rc::new(RefCell::new(FTable::new()));
+                let vt = Rc::new(RefCell::new(VTable::new()));
+                let args = new_ast(Ctr::String("test".to_string()), Ctr::None);
+                if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(test_external_func)))
+                {
+                    print!("Error declaring external func: {}", s);
+                    assert!(false);
+                }
+
+                let func: Rc<RefCell<Function>>;
+                if let Some(f) = ft.borrow().get(&"echo".to_string()) {
+                    func = f.clone();
+                } else {
+                    print!("failed to retrieve function!");
+                    assert!(false);
+                    return;
+                }
+
+                match func_call(func, args, vt, ft) {
+                    Ok(ret) => match ret {
+                        Ctr::String(b) => assert!(b == "test"),
+                        _ => {
+                            print!("Invalid return from func. Got {:?}\n", ret);
+                            assert!(false);
+                        }
+                    },
+                    Err(e) => {
+                        print!("Call to function failed: {}\n", e);
+                        assert!(false);
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn decl_and_call_external_func_multi_body() {
+        match lex("((input) (input))".to_string()) {
+            Err(e) => panic!("{}", e),
+            Ok(finner) => {
+                let test_external_func: Function = Function {
+                    name: String::from("echo_2"),
+                    loose_syms: false,
+                    eval_lazy: false,
+                    args: Args::Lazy(1),
+                    function: Operation::External(ExternalOperation {
+                        arg_syms: vec!["input".to_string()],
+                        ast: finner,
+                    }),
+                };
+                let ft = Rc::new(RefCell::new(FTable::new()));
+                let vt = Rc::new(RefCell::new(VTable::new()));
+                let args = new_ast(Ctr::String("test".to_string()), Ctr::None);
+                if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(test_external_func)))
+                {
+                    print!("Error declaring external func: {}", s);
+                    assert!(false);
+                }
+
+                let func: Rc<RefCell<Function>>;
+                if let Some(f) = ft.borrow().get(&"echo_2".to_string()) {
+                    func = f.clone();
+                } else {
+                    print!("failed to retrieve function!");
+                    assert!(false);
+                    return;
+                }
+
+                match func_call(func, args, vt, ft) {
+                    Ok(ret) => match ret {
+                        Ctr::String(s) => {
+                            assert!(s == "test");
+                        }
+                        _ => {
+                            print!("Invalid return from function {:#?}. Should have recieved single string", ret);
+                            assert!(false);
+                            return;
+                        }
+                    },
+                    Err(e) => {
+                        print!("Call to function failed: {}\n", e);
+                        assert!(false);
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn decl_and_call_func_with_nested_call() {
+        let inner_func: Function = Function {
+            name: String::from("test_inner"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Strict(vec![Type::Bool]),
+            function: Operation::Internal(Box::new(
+                |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                    let inner = a.borrow();
+                    if let Ctr::Bool(b) = &inner.car {
+                        if *b {
+                            Ctr::String("test".to_string())
+                        } else {
+                            Ctr::None
+                        }
+                    } else {
+                        Ctr::None
+                    }
+                },
+            )),
+        };
+
+        match lex("((test_inner true))".to_string()) {
+            Err(e) => panic!("{}", e),
+            Ok(finner) => {
+                let outer_func: Function = Function {
+                    name: String::from("test_outer"),
+                    loose_syms: false,
+                    eval_lazy: false,
+                    args: Args::Lazy(1),
+                    function: Operation::External(ExternalOperation {
+                        arg_syms: vec!["input".to_string()],
+                        ast: finner,
+                    }),
+                };
+
+                let ft = Rc::new(RefCell::new(FTable::new()));
+                let vt = Rc::new(RefCell::new(VTable::new()));
+                let args = new_ast(Ctr::Bool(true), Ctr::None);
+
+                if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(inner_func))) {
+                    print!("Error declaring inner func: {}", s);
+                    assert!(false);
+                }
+                if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(outer_func))) {
+                    print!("Error declaring outer func: {}", s);
+                    assert!(false);
+                }
+
+                let func: Rc<RefCell<Function>>;
+                if let Some(f) = ft.borrow().get(&"test_outer".to_string()) {
+                    func = f.clone();
+                } else {
+                    print!("failed to retrieve function!");
+                    assert!(false);
+                    return;
+                }
+
+                match func_call(func, args, vt, ft) {
+                    Ok(ret) => match ret {
+                        Ctr::String(b) => assert!(b == "test"),
+                        _ => {
+                            print!("Invalid return from func. Got {:?}\n", ret);
+                            assert!(false);
+                        }
+                    },
+                    Err(e) => {
+                        print!("Call to function failed: {}\n", e);
+                        assert!(false);
+                    }
+                }
+            }
+        }
+    }
+
+    /* This test removed because it would make more sense to test this functionality in eval tests
+     * this function tested the evaluation of a complex argument ast that could be reduced in eval
+
+    #[test]
+    fn decl_and_call_func_eval_arg() {
+        let is_true_func: Function = Function{
+            name: String::from("is_true?"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Strict(vec![Type::Bool]),
+            function: Operation::Internal(
+                |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                    let inner = a.borrow();
+                    if let Ctr::Bool(b) = &inner.car {
+                        if *b {
+                            Ctr::String("test".to_string())
+                        } else {
+                            Ctr::None
+                        }
+                    } else {
+                        Ctr::None
+                    }
+                }
+            )
+        };
+
+        let echo_func: Function = Function{
+            name: String::from("echo"),
+            loose_syms: false,
+            eval_lazy: false,
+            args: Args::Lazy(1),
+            function: Operation::External(
+                ExternalOperation{
+                    arg_syms: vec!["input".to_string()],
+                    ast: new_ast(Ctr::Symbol("input".to_string()), Ctr::None)
+                }
+            )
+        };
+
+        let ft = Rc::new(RefCell::new(FTable::new()));
+        let vt = Rc::new(RefCell::new(VTable::new()));
+        let args = new_ast(
+            Ctr::Seg(new_ast(
+                Ctr::Symbol("is_true?".to_string()),
+                Ctr::Seg(new_ast(
+                    Ctr::Bool(true),
+                    Ctr::None)))),
+            Ctr::None);
+
+        if let Some(s) = func_declare(ft.clone(),
+                                      Rc::new(RefCell::new(is_true_func))) {
+            print!("Error declaring inner func: {}", s);
+            assert!(false);
+        }
+        if let Some(s) = func_declare(ft.clone(),
+                                      Rc::new(RefCell::new(echo_func))) {
+            print!("Error declaring outer func: {}", s);
+            assert!(false);
+        }
+
+        let func: Rc<RefCell<Function>>;
+        if let Some(f) = ft.borrow().get(&"echo".to_string()) {
+            func = f.clone();
+        } else {
+            print!("failed to retrieve function!");
+            assert!(false);
+            return;
+        }
+
+        match func_call(func, args, vt, ft) {
+            Ok(ret) => {
+                match ret {
+                    Ctr::String(b) => assert!(b == "test"),
+                    _ => {
+                        print!("Invalid return from func. Got {:?}\n", ret);
+                        assert!(false);
+                    }
+                }
+            },
+            Err(e) => {
+                print!("Call to function failed: {}\n", e);
+                assert!(false);
+            }
+        }
+    }*/
+
+    /*
+    // TODO: These tests need completion!
+    #[test]
+    fn eval_lazy_func_call() {
+
+    }
+
+    #[test]
+    fn sym_loose_func_call() {
+
+    }
+
+    #[test]
+    fn too_many_args() {
+
+    }
+
+    #[test]
+    fn not_enough_args() {
+
+    }
+
+    #[test]
+    fn bad_eval_arg() {
+
+    }
+
+    #[test]
+    fn bad_eval_fn_body() {
+
+    }*/
+}

the_rewrite/tests/test_vars.rs

@@ -0,0 +1,64 @@
+mod var_lib_tests {
+    use relish::ast::{eval, lex, Ctr, FTable, VTable};
+    use relish::stdlib::get_stdlib;
+    use std::cell::RefCell;
+    use std::rc::Rc;
+
+    #[test]
+    fn test_variable_export_and_lookup() {
+        let doc1 = "(export test 1)";
+        let doc2 = "(concat test)";
+        let result = "1";
+        let vt = Rc::new(RefCell::new(VTable::new()));
+        let ft: Rc<RefCell<FTable>>;
+        match get_stdlib(vt.clone()) {
+            Ok(f) => ft = f,
+            Err(s) => {
+                ft = Rc::new(RefCell::new(FTable::new()));
+                println!("Couldnt get stdlib: {}!", s);
+                assert!(false);
+            }
+        }
+
+        match lex(doc1.to_string()) {
+            Err(s) => {
+                println!("Couldnt lex {}: {}", doc1, s);
+                assert!(false);
+            }
+
+            Ok(tree) => match eval(tree, vt.clone(), ft.clone(), false) {
+                Err(s) => {
+                    println!("Couldnt eval {}: {}", doc2, s);
+                    assert!(false);
+                }
+
+                Ok(ctr) => {
+                    println!("{:#?}", vt);
+                    match ctr {
+                        Ctr::None => assert!(true),
+                        _ => assert!(false),
+                    }
+                }
+            },
+        }
+
+        match lex(doc2.to_string()) {
+            Err(s) => {
+                println!("Couldnt lex {}: {}", doc2, s);
+                assert!(false);
+            }
+
+            Ok(tree) => match eval(tree, vt.clone(), ft.clone(), false) {
+                Err(s) => {
+                    println!("Couldnt eval {}: {}", doc2, s);
+                    assert!(false);
+                }
+
+                Ok(ctr) => match ctr {
+                    Ctr::String(s) => assert_eq!(s, result),
+                    _ => assert!(false),
+                },
+            },
+        }
+    }
+}