significant refactor and simplification

Readme.org

@@ -126,9 +126,9 @@ one of these may fix borrow checker insanity
 **** DONE YEET AST EVERYWHERE. PASS AROUND A SEG REF.
 *** TODO refactor code into more digestible, better organized pieces
 **** DONE combine var and func table into global sym table
-**** TODO code deduplication and cleanup in sym table
+**** DONE refactor and reimplement eval
-**** TODO refactor and reimplement eval
 **** TODO (test and get it working)
+**** TODO lex/eval/e2e tests for var that holds callback func
 *** TODO Rudimentary Control Flow
 **** TODO if clause
 **** TODO loop clause
@@ -141,8 +141,8 @@ one of these may fix borrow checker insanity
 **** DONE manual verification of config defaults
 *** TODO Help function
 *** TODO Env function
-*** TODO User variable declaration
+*** DONE User variable declaration
-*** TODO User function declaration
+*** DONE User function declaration
 *** TODO Load (load a script) function
 Pull/Refactor the logic out of the configure functions.
 Optionally return a list of new variables and/or functions?

src/eval.rs

@@ -15,22 +15,21 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-
+use crate::sym::{SYM_TABLE, Symbol, ValueType};
 use crate::segment::{Seg, Ctr};
-use crate::sym::SYM_TABLE;
 
 /* iterates over a syntax tree
  * returns a NEW LIST of values
  * representing the simplest possible form of the input
  */
-
+pub fn eval (
-pub fn eval(
     ast: &Seg,
-    sym_loose: bool,
+    expect_all_symbols_defined: bool,
-    call_lazy: bool,
+    simplify_function_branches: bool,
 ) -> Result<Box<Ctr>, String> {
     // data to return
     let mut ret = Box::from(Ctr::None);
+    let mut first = true;
 
     // to be assigned from cloned/evaled data
     let mut car;
@@ -40,60 +39,69 @@ pub fn eval(
     let mut arg_car = &ast.car;
     let mut arg_cdr = &ast.cdr;
 
-    // theres probably a better way to do this
+    let table_handle = SYM_TABLE.lock().unwrap();
-    let mut binding_for_vtable_get;
-
-    // doing an initial variable check here allows us
-    // to find functions passed in as variables
-    if let Ctr::Symbol(tok) = &**arg_car {
-        binding_for_vtable_get = vars.get(tok.clone());
-        if let Some(ref val) = binding_for_vtable_get {
-            arg_car = &val;
-        }
-    }
-
-    // Is ast a function call?
-    if !call_lazy {
-        if let Ctr::Symbol(ref tok) = &**arg_car {
-            match *ast.cdr {
-                Ctr::Seg(ref ast) => {
-                    if let Some(ref 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(ref 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!")),
-            }
-        }
-    }
 
     // iterate over ast and build out ret
     let mut none = false;
     while !none {
-        match &**arg_car {
+        let mut prefetched_function: Option<&Symbol> = None;
-            Ctr::Seg(ref inner) => {
+        while let Ctr::Symbol(ref tok) = **arg_car {
-                match eval(inner, vars, funcs, sym_loose, call_lazy) {
+            prefetched_function = table_handle.get(tok);
-                    Ok(res) => car = res,
+            if let Some(sym_ref) = prefetched_function {
-                    Err(e) => return Err(format!("Evaluation error: {}", e)),
+                if let ValueType::VarForm(ref value) = sym_ref.value {
+                    arg_car = value;
+                } else {
+                    break;
+                }
+            } else if !expect_all_symbols_defined {
+                return Err(format!("evaluation error: undefined symbol {}", tok))
+            } else {
+                break
             }
         }
 
-            Ctr::Symbol(ref tok) => {
+        match **arg_car {
-                binding_for_vtable_get = vars.get(tok.clone());
+            Ctr::Seg(ref inner) => {
-                if let Some(ref val) = binding_for_vtable_get {
+                match eval(inner, expect_all_symbols_defined, simplify_function_branches) {
-                    car = val.clone();
+                    Ok(res) => car = res,
-                } else if sym_loose {
+                    Err(e) => return Err(format!("evaluation error: {}", e)),
-                    car = arg_car.clone()
+                }
+            }
+
+            // im tired please simplify this
+            Ctr::Symbol(_) => {
+                if simplify_function_branches && first {
+                    if let Some(func) = prefetched_function {
+                        if let Ctr::Seg(ref candidates) = **arg_cdr {
+                            let fc: Result<Box<Ctr>, String>;
+                            match eval(candidates, expect_all_symbols_defined, false) {
+                                Ok(res) => {
+                                    match *res {
+                                        Ctr::Seg(ref args) => {
+                                            fc = func.call(args);
+                                        },
+                                        _ => {
+                                            fc = func.call(&Seg::from_mono(res.clone()))
+                                        }
+                                    }
+                                    match fc {
+                                        Ok(datum) => car = datum,
+                                        Err(e) => return Err(format!("call to {} failed: {}", func.name, e))
+                                    }
+                                }
+                                Err(e) => return Err(format!("evaluation error: {}", e))
+                            }
                         } else {
-                    return Err(format!("Undefined variable: {}", tok.clone()));
+                            match func.call(&Seg::new()) {
+                                Ok(res) => car = res,
+                                Err(e) => return Err(format!("call to {} failed: {}", func.name, e))
+                            }
+                        }
+                    } else {
+                        car = arg_car.clone();
+                    }
+                } else {
+                    car = arg_car.clone();
                 }
             }
 
@@ -102,16 +110,25 @@ pub fn eval(
             }
         }
 
-        match &**arg_cdr {
+        // weird tree but okay
-            Ctr::Symbol(ref tok) => {
+        while let Ctr::Symbol(ref tok) = **arg_cdr {
-                if let Some(val) = vars.get(tok.clone()) {
+            prefetched_function = table_handle.get(tok);
-                    cdr = val.clone();
+            if let Some(sym_ref) = prefetched_function {
-                } else if sym_loose {
+                if let ValueType::VarForm(ref value) = sym_ref.value {
-                    cdr = ast.cdr.clone()
+                    arg_cdr = value;
                 } else {
-                    return Err(format!("Undefined variable: {}", tok.clone()));
+                    break;
+                }
+            } else if !expect_all_symbols_defined {
+                return Err(format!("evaluation error: undefined symbol {}", tok))
+            } else {
+                break
+            }
         }
 
+        match **arg_cdr {
+            Ctr::Symbol(_) => {
+                cdr = arg_cdr.clone();
                 none = true;
             }
 
@@ -125,7 +142,6 @@ pub fn eval(
                 arg_cdr = &next.cdr
             }
 
-            // if OTHER: clone and set, and then end
             _ => {
                 cdr = ast.cdr.clone();
                 none = true;
@@ -137,7 +153,10 @@ pub fn eval(
                 none = true;
             }
         }
+
+        first = false;
     }
 
-    return Ok(ret);
+    Ok(ret)
 }
+

src/lex.rs

@@ -23,7 +23,7 @@ const UNMATCHED_LIST_DELIM: &str = "Unmatched list delimiter in input";
 /* takes a line of user input
  * returns an unsimplified tree of tokens.
  */
-pub fn lex<'a>(document: &'a String) -> Result<Box<Seg>, String> {
+pub fn lex(document: &String) -> Result<Box<Seg>, String> {
     if !document.is_ascii() {
         return Err("document may only contain ascii characters".to_string());
     }
@@ -42,7 +42,7 @@ pub fn lex<'a>(document: &'a String) -> Result<Box<Seg>, String> {
  * Returns Ok(Rc<Seg>) if lexing passes
  * Returns Err(String) if an error occurs
  */
-fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
+fn process(document: &String) -> Result<Box<Seg>, String> {
     let doc_len = document.len();
 
     if doc_len == 0 {
@@ -87,7 +87,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
                 // set alloc_list
                 if delim == ')' {
                     alloc_list = true;
-                    if ref_stack.len() < 1 {
+                    if ref_stack.is_empty() {
                         return Err("too many end parens".to_string());
                     }
                 }
@@ -101,7 +101,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
         // try to generalize all whitespace
         if !needs_alloc && char::is_whitespace(c) && !is_str {
             // dont make empty tokens just because the document has consecutive whitespace
-            if token.len() == 0 {
+            if token.is_empty() {
                 continue;
             }
             needs_alloc = true;
@@ -116,7 +116,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
                         continue;
                     }
 
-                    if token != "" {
+                    if !token.is_empty() {
                         return Err("list started in middle of another token".to_string());
                     }
 
@@ -147,7 +147,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
          * 2. Handle expansion of current list ref
          */
         } else {
-            if token.len() == 0 && !is_str && !alloc_list {
+            if token.is_empty() && !is_str && !alloc_list {
                 return Err("Empty token".to_string());
             }
 
@@ -158,7 +158,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
                 is_str = false;
                 token = String::new();
                 current_seg.append(obj);
-            } else if token.len() > 0 {
+            } else if !token.is_empty() {
                 if token == "true" {
                     obj = Box::from(Ctr::Bool(true));
                 } else if token == "false" {
@@ -179,7 +179,7 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
 
             if alloc_list {
                 // return if we have finished the document
-                if ref_stack.len() == 0 {
+                if ref_stack.is_empty() {
                     return Ok(Box::new(current_seg));
                 }
 
@@ -199,9 +199,10 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
     }
 
     if is_str {
-        return Err(UNMATCHED_STR_DELIM.to_string());
+        Err(UNMATCHED_STR_DELIM.to_string())
+    } else {
+        Err(UNMATCHED_LIST_DELIM.to_string())
     }
-    return Err(UNMATCHED_LIST_DELIM.to_string());
 }
 
 /* Returns true if token
@@ -209,13 +210,12 @@ fn process<'a>(document: &'a String) -> Result<Box<Seg>, String> {
  *
  * else returns false
  */
-fn tok_is_symbol(token: &String) -> Option<String> {
+fn tok_is_symbol(token: &str) -> Option<String> {
-    let tok = token.as_str();
+    for t in token.chars() {
-    for t in tok.chars() {
+        if !t.is_alphanumeric() && t != '-' && t != '_' {
-        if !t.is_alphabetic() && !t.is_digit(10) && !(t == '-') && !(t == '_') {
             return None;
         }
     }
 
-    return Some(String::from(tok));
+    Some(String::from(token))
 }

src/lib.rs

@@ -19,24 +19,23 @@
 mod config;
  */
 mod eval;
-mod func;
 mod lex;
 mod segment;
-mod vars;
+mod sym;
+mod stl;
 /*mod stl;
 mod str;*/
 
 extern crate lazy_static;
 
 pub mod ast {
-    pub use crate::eval::eval;
+//    pub use crate::eval::eval;
     pub use crate::lex::lex;
     pub use crate::segment::{Ctr, Seg, Type};
-    pub use crate::sym::{
+/*    pub use crate::sym::{
         SYM_TABLE, SymTable, Symbol,
-        UserFn, ValueType, Args,
+        UserFn, ValueType, Args
-        LIB_EXPORT_ENV, LIB_EXPORT_NO_ENV
+    };*/
-    };
 }
 
 /*pub mod stdlib {

src/segment.rs

@@ -20,13 +20,13 @@ use std::ops::Index;
 
 // Container
 #[derive(Debug, Default)]
-pub enum Ctr<'a> {
+pub enum Ctr {
     Symbol(String),
     String(String),
     Integer(i128),
     Float(f64),
     Bool(bool),
-    Seg(Seg<'a>),
+    Seg(Seg),
     #[default]
     None,
 }
@@ -49,29 +49,29 @@ pub enum Type {
  * I was going to call it Cell and then I learned about
  * how important RefCells were in Rust
  */
-#[derive(Debug)]
+#[derive(Debug, Default)]
-pub struct Seg<'a> {
+pub struct Seg {
     /* "Contents of Address Register"
      *  Historical way of referring to the first value in a cell.
      */
-    pub car: Box<Ctr<'a>>,
+    pub car: Box<Ctr>,
 
     /* "Contents of Decrement Register"
      *  Historical way of referring to the second value in a cell.
      */
-    pub cdr: Box<Ctr<'a>>,
+    pub cdr: Box<Ctr>,
 
     /* Stupid hack that makes rust look foolish.
      * Needed to determine variance of lifetime.
      * How this is an acceptable solution I have
      * not a single clue.
      */
-    _lifetime_variance_determinant: PhantomData<&'a ()>
+    _lifetime_variance_determinant: PhantomData<()>
 }
 
 static NOTHING: Ctr = Ctr::None;
 
-impl Ctr<'_> {
+impl Ctr {
     pub fn to_type(&self) -> Type {
         match self {
             Ctr::Symbol(_s) => Type::Symbol,
@@ -86,14 +86,14 @@ impl Ctr<'_> {
 
 }
 
-impl<'a> Seg<'a> {
+impl Seg {
     /* recurs over tree assumed to be list in standard form
      * appends object to end of list
      *
      * TODO: figure out how not to call CLONE on a CTR via obj arg
      * TODO: return result
      */
-    pub fn append<'b>(&mut self, obj: Box<Ctr<'a>>) {
+    pub fn append(&mut self, obj: Box<Ctr>) {
         if let Ctr::None = &*(self.car) {
             self.car = obj;
             return
@@ -127,16 +127,16 @@ impl<'a> Seg<'a> {
         }
     }
 
-    pub fn from_mono(arg: Box<Ctr<'a>>) -> Seg<'a> {
+    pub fn from_mono(arg: Box<Ctr>) -> Seg {
-        return Seg{
+        Seg {
             car: arg,
             cdr: Box::new(Ctr::None),
             _lifetime_variance_determinant: PhantomData,
         }
     }
 
-    pub fn from(car: Box<Ctr<'a>>, cdr: Box<Ctr<'a>>) -> Seg<'a> {
+    pub fn from(car: Box<Ctr>, cdr: Box<Ctr>) -> Seg {
-        return Seg{
+        Seg {
             car,
             cdr,
             _lifetime_variance_determinant: PhantomData,
@@ -152,8 +152,12 @@ impl<'a> Seg<'a> {
         len
     }
 
-    pub fn new() -> Seg<'a> {
+    pub fn is_empty(&self) -> bool {
-        return Seg{
+        self.len() == 0
+    }
+
+    pub fn new() -> Seg {
+        Seg {
             car: Box::new(Ctr::None),
             cdr: Box::new(Ctr::None),
             _lifetime_variance_determinant: PhantomData,
@@ -170,7 +174,7 @@ fn seg_to_string(s: &Seg, parens: bool) -> String {
     }
     string.push(' ');
     match &*(s.cdr) {
-        Ctr::Seg(inner) => string.push_str(&seg_to_string(&inner, false)),
+        Ctr::Seg(inner) => string.push_str(&seg_to_string(inner, false)),
         Ctr::None => {string.pop();},
         _ => string.push_str(&s.cdr.to_string()),
     }
@@ -179,9 +183,9 @@ fn seg_to_string(s: &Seg, parens: bool) -> String {
     string
 }
 
-impl<'a> Clone for Seg<'a> {
+impl Clone for Seg {
-    fn clone(&self) -> Seg<'a> {
+    fn clone(&self) -> Seg {
-        return Seg{
+        Seg {
             car: self.car.clone(),
             cdr: self.cdr.clone(),
             _lifetime_variance_determinant: PhantomData,
@@ -189,8 +193,8 @@ impl<'a> Clone for Seg<'a> {
     }
 }
 
-impl<'a> Index<usize> for Seg<'a> {
+impl Index<usize> for Seg {
-    type Output = Ctr<'a>;
+    type Output = Ctr;
 
     fn index(&self, idx: usize) -> &Self::Output {
         if idx == 0 {
@@ -201,25 +205,25 @@ impl<'a> Index<usize> for Seg<'a> {
             return s.index(idx - 1)
         }
 
-        return &NOTHING;
+        &NOTHING
     }
 }
 
-impl<'a> Clone for Ctr<'a> {
+impl Clone for Ctr {
-    fn clone(&self) -> Ctr<'a> {
+    fn clone(&self) -> Ctr {
         match self {
             Ctr::Symbol(s) => Ctr::Symbol(s.clone()),
             Ctr::String(s) => Ctr::String(s.clone()),
-            Ctr::Integer(s) => Ctr::Integer(s.clone()),
+            Ctr::Integer(s) => Ctr::Integer(*s),
-            Ctr::Float(s) => Ctr::Float(s.clone()),
+            Ctr::Float(s) => Ctr::Float(*s),
-            Ctr::Bool(s) => Ctr::Bool(s.clone()),
+            Ctr::Bool(s) => Ctr::Bool(*s),
             Ctr::Seg(s) => Ctr::Seg(s.clone()),
             Ctr::None => Ctr::None,
         }
     }
 }
 
-impl fmt::Display for Ctr<'_> {
+impl fmt::Display for Ctr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Ctr::Symbol(s) => write!(f, "{}", s),
@@ -239,25 +243,38 @@ impl fmt::Display for Ctr<'_> {
     }
 }
 
-impl fmt::Display for Seg<'_> {
+impl fmt::Display for Seg {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", seg_to_string(self, true))
     }
 }
 
-impl Type {
+impl fmt::Display for Type {
-    pub fn to_string(&self) -> String {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let ret: &str;
+        let ret: &str = match self {
-        match self {
+            Type::Symbol => "symbol",
-            Type::Symbol => ret = "symbol",
+            Type::String => "string",
-            Type::String => ret = "string",
+            Type::Integer => "integer",
-            Type::Integer => ret = "integer",
+            Type::Float => "float",
-            Type::Float => ret = "float",
+            Type::Bool => "bool",
-            Type::Bool => ret = "bool",
+            Type::Seg => "segment",
-            Type::Seg => ret = "segment",
+            Type::None => "none",
-            Type::None => ret = "none",
+        };
-        }
 
-        ret.to_owned()
+        write!(f, "{}", ret)
+    }
+}
+
+impl std::convert::From<String> for Type {
+    fn from(value: String) -> Self {
+        match value.as_str() {
+            "symbol" => Type::Symbol,
+            "string" => Type::String,
+            "integer" => Type::Integer,
+            "float" => Type::Float,
+            "bool" => Type::Bool,
+            "segment" => Type::Seg,
+            _ => Type::None,
+        }
     }
 }

src/stl.rs

@@ -0,0 +1,118 @@
+/* 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, Type};
+use crate::eval::eval;
+use crate::sym::{SYM_TABLE, Symbol, ValueType, Args, UserFn};
+use std::env;
+
+/*
+// the stdlib var export function with env_sync on
+static LIB_STORE_ENV: Symbol = Symbol {
+    name: String::from("export"),
+    args: Args::Lazy(2),
+    value: ValueType::Internal(Box::new( |ast: &Seg| -> Ctr {
+        _store_callback(ast, true)
+    },
+    )),
+    has_undefined_symbols: false,
+};
+
+// the stdlib var export function with env_sync off
+pub static LIB_STORE_NO_ENV: Symbol = Symbol {
+    name: String::from("export"),
+    args: Args::Lazy(2),
+    value: ValueType::Internal(Box::new( |ast: &Seg| -> Ctr {
+        _store_callback(ast, false)
+    },
+    )),
+    has_undefined_symbols: false,
+};*/
+
+// TODO : declare function if arg list is long enough
+fn _store_callback (ast: &Seg, env_cfg: bool) -> Ctr {
+    let mut table_handle = SYM_TABLE.lock().unwrap();
+    let is_var = ast.len() == 2;
+    if let Ctr::Symbol(ref identifier) = *ast.car {
+        match &*ast.cdr {
+            Ctr::Seg(data_tree) if is_var => match eval(&Box::new(data_tree), true, true) {
+                Ok(seg) => if let Ctr::Seg(ref val) = *seg {
+                    table_handle.insert(identifier.clone(), Symbol{
+                        value: ValueType::VarForm(val.car.clone()),
+                        name: identifier.clone(),
+                        args: Args::None,
+                        has_undefined_symbols: false,
+                    });
+                    if env_cfg {
+                        env::set_var(identifier.clone(), val.car.to_string());
+                    }
+                } else {
+                    eprintln!("impossible args to export")
+                },
+                Err(e) => eprintln!("couldnt eval symbol: {}", e),
+            },
+            Ctr::Seg(data_tree) if !is_var => {
+                if let Ctr::Seg(ref args) = *data_tree.car {
+                    let mut arg_list = vec![];
+                    if !args.circuit(&mut |c: &Ctr| -> bool {
+                        if let Ctr::Symbol(ref arg) = c {
+                            arg_list.push(arg.clone());
+                            true
+                        } else {
+                            false
+                        }
+                    }) {
+                        eprintln!("all arguments defined for function must be of type symbol");
+                        return Ctr::None;
+                    };
+
+                    if let Ctr::Seg(ref bodies) = *data_tree.cdr {
+                        table_handle.insert(identifier.clone(), Symbol{
+                            value: ValueType::FuncForm(UserFn{
+                                ast: Box::new(bodies.clone()),
+                                arg_syms: arg_list.clone(),
+                            }),
+                            name: identifier.clone(),
+                            args: Args::Strict(arg_list
+                                               .into_iter()
+                                               .map(Type::from)
+                                               .collect()),
+                            has_undefined_symbols: false,
+                        });
+                    } else {
+                        eprintln!("expected one or more function bodies in function definition");
+                        return Ctr::None;
+                    }
+                } else {
+                    eprintln!("expected list of arguments in function definition");
+                    return Ctr::None;
+                }
+            }
+            Ctr::None => {
+                table_handle.remove(&identifier.to_string());
+                if env_cfg {
+                    env::remove_var(identifier);
+                }
+            },
+            _ =>  eprintln!("args not in standard form"),
+        }
+    } else {
+        eprintln!("first argument to export must be a symbol");
+    }
+    Ctr::None
+}
+

src/sym.rs

@@ -0,0 +1,220 @@
+/* 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 std::collections::HashMap;
+use std::sync::Mutex;
+use lazy_static::lazy_static;
+
+pub type SymTable = HashMap<String, Symbol>;
+
+lazy_static! {
+    pub static ref SYM_TABLE: Mutex<SymTable> = {
+        Mutex::new(SymTable::new())
+    };
+}
+
+#[derive(Debug, Clone)]
+pub struct UserFn {
+    // 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>,
+    // list of argument string tokens
+    pub arg_syms: Vec<String>,
+}
+
+/* A symbol may either be a pointer to a function
+ * or a syntax tree to eval with the arguments or
+ * a simple variable declaration (which can also
+ * be a macro)
+ */
+#[derive(Clone)]
+pub enum ValueType {
+    Internal(Box<fn(&Seg) -> Ctr>),
+    FuncForm(UserFn),
+    VarForm(Box<Ctr>)
+}
+
+/* Function Args
+ * If Lazy, is an integer denoting number of args
+ * If Strict, is a list of type tags denoting argument type.
+ */
+#[derive(Clone)]
+pub enum Args {
+    Lazy(u128),
+    Strict(Vec<Type>),
+    Infinite,
+    None
+}
+
+#[derive(Clone)]
+pub struct Symbol {
+    pub value: ValueType,
+    pub name: String,
+    pub args: Args,
+    pub has_undefined_symbols: bool,
+}
+
+impl Args {
+    fn validate_inputs(&self, args: &Seg) -> Result<(), String> {
+        match self {
+            Args::None => {
+                if args.is_empty() {
+                    return Ok(())
+                } else {
+                    return Err("expected no args".to_string())
+                }
+            },
+            Args::Infinite => {
+                if !args.is_empty() {
+                    return Ok(())
+                } else {
+                    return Err("expected args but none were provided".to_string())
+                }
+            },
+
+            Args::Lazy(ref num) => {
+                let called_arg_count = args.len();
+                if *num == 0 {
+                    if let Ctr::None = *args.car {
+                        //pass
+                    } else {
+                        return Err("expected 0 args. Got one or more.".to_string());
+                    }
+                } else if *num != called_arg_count {
+                    return Err(format!(
+                        "expected {} args. Got {}.",
+                        num, called_arg_count
+                    ));
+                }
+            }
+
+            Args::Strict(ref arg_types) => {
+                let mut idx: usize = 0;
+                let passes = 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;
+                    }
+                    false
+                });
+
+                if passes && idx < (arg_types.len() - 1) {
+                    return Err(format!(
+                        "{} too few arguments",
+                        arg_types.len() - (idx + 1)
+                    ));
+                }
+
+                if !passes {
+                    if idx < (arg_types.len() - 1) {
+                        return Err(format!(
+                            "argument {} is of wrong type (expected {})",
+                            idx + 1,
+                            arg_types[idx]
+                        ));
+                    }
+                    if idx == (arg_types.len() - 1) {
+                        return Err("too many arguments".to_string());
+                    }
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl Symbol {
+    /* call
+     * routine is called by eval when a symbol is expanded
+     */
+    pub fn call(
+        &self,
+        args: &Seg,
+    ) -> Result<Box<Ctr>, String> {
+        if let Err(msg) = self.args.validate_inputs(args) {
+            return Err(format!("failure to call {}: {}", self.name, msg));
+        }
+
+        match &self.value {
+            ValueType::VarForm(ref f) => Ok(Box::new(*f.clone())),
+            ValueType::Internal(ref f) => Ok(Box::new(f(args))),
+            ValueType::FuncForm(ref f) => {
+                // stores any value overwritten by local state
+                // If this ever becomes ASYNC this will need to
+                // become a more traditional stack design, and the
+                // global table will need to be released
+                let mut holding_table = SymTable::new();
+
+                // Prep var table for function execution
+                for n in 0..f.arg_syms.len() {
+                    if let Some(old) = SYM_TABLE.lock().unwrap()
+                        .insert(f.arg_syms[n].clone(), Symbol{
+                            name: f.arg_syms[n].clone(),
+                            value: ValueType::VarForm(Box::new(args[n].clone())),
+                            args: Args::None,
+                            has_undefined_symbols: false,
+                        })
+                    {
+                        holding_table.insert(f.arg_syms[n].clone(), old);
+                    }
+                }
+
+                // execute function
+                let mut result: Box<Ctr>;
+                let mut iterate = &*(f.ast);
+                loop {
+                    if let Ctr::Seg(ref data) = *iterate.car {
+                        match eval(data, !self.has_undefined_symbols, true) {
+                            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!"),
+                    }
+                }
+
+                // clear local vars and restore previous values
+                for n in 0..f.arg_syms.len() {
+                    SYM_TABLE.lock().unwrap().remove(&f.arg_syms[n]);
+                    if let Some(val) = holding_table.remove(&f.arg_syms[n]) {
+                        SYM_TABLE.lock().unwrap().insert(f.arg_syms[n].clone(), val);
+                    }
+                }
+
+                Ok(result)
+            }
+        }
+    }
+}
+

sym.rs

@@ -1,294 +0,0 @@
-/* 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::{VAR_TABLE, VTable, LIB_EXPORT};
-use std::collections::HashMap;
-use std::convert::TryInto;
-use lazy_static::lazy_static;
-
-lazy_static! {
-    pub static ref SYM_TABLE: SymTable<'static> = {
-        let mut tab = SymTable::new();
-        tab.declare(LIB_EXPORT);
-        tab
-    };
-}
-
-
-pub struct SymTable<'a> (HashMap<String, &'a Symbol>);
-
-#[derive(Debug)]
-pub struct UserFn<'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 symbol may either be a pointer to a function
- * or a syntax tree to eval with the arguments or
- * a simple variable declaration (which can also
- * be a macro)
- */
-pub enum ValueType<'a> {
-    Internal(Box<dyn Fn(&'a Seg) -> Ctr<'a>>),
-    UserFn(ExternalOperation<'a>),
-    UserVar(Box<Ctr<'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>),
-}
-
-impl Args {
-    fn validate_inputs(&self, args: &Seg) -> Result<(), String> {
-        match self {
-            Args::Lazy(ref num) => {
-                let called_arg_count = args.len() as i128;
-                if *num == 0 {
-                    if let Ctr::None = *args.car {
-                        //pass
-                    } else {
-                        return Err("Expected 0 args. Got one or more.".to_string());
-                    }
-                } else if *num > -1 && (*num != called_arg_count) {
-                    return Err(format!(
-                        "Expected {} args. Got {}.",
-                        num, called_arg_count
-                    ));
-                }
-            }
-
-            Args::Strict(ref arg_types) => {
-                let mut idx: usize = 0;
-                let passes = 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 few arguments",
-                        arg_types.len() - (idx + 1)
-                    ));
-                }
-
-                if !passes {
-                    if idx < (arg_types.len() - 1) {
-                        return Err(format!(
-                            "argument {} is of wrong type (expected {})",
-                            idx + 1,
-                            arg_types[idx].to_string()
-                        ));
-                    }
-                    if idx == (arg_types.len() - 1) {
-                        return Err("too many arguments".to_string());
-                    }
-                }
-            }
-        }
-
-        Ok(())
-    }
-}
-
-
-pub struct Symbol {
-    pub value: ValueType,
-    pub name: String,
-
-    // has no meaning for UserVar values
-    pub args: Args,
-
-    // dont fail on undefined symbol (passed to eval)
-    // has no meaning for UserVar values
-    pub loose_syms: bool,
-
-    // dont evaluate args at all. leave that to the function
-    // has no meaning for UserVar values
-    pub eval_lazy: bool,
-}
-
-impl<'a, 'b> Symbol {
-    /* call
-     * routine is called by eval when a function call is detected
-     */
-    pub fn func_call(
-        &self,
-        args: &'b Seg<'b>,
-    ) -> Result<Box<Ctr<'c>>, String> {
-        // put args in simplest desired form
-        let evaluated_args;
-        match eval(args, self.loose_syms, self.eval_lazy) {
-            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
-                ))
-            }
-        }
-
-        if let UserVar(_s) = self {
-            return evaluated_args;
-        }
-
-        if let Err(msg) = self.args.validate_inputs(evaluated_args) {
-            return Err(format!("failure to call {}: {}", self.name, msg));
-        }
-
-        /* 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))),
-            Operation::External(ref f) => {
-                let mut holding_table = VTable::new();
-
-                // Prep var table for function execution
-                for n in 0..f.arg_syms.len() {
-                    let iter_arg = evaluated_args[n];
-                    if let Some(val) = VAR_TABLE.get(f.arg_syms[n]) {
-                        holding_table.insert(f.arg_syms[n].clone(), val);
-                    }
-
-                    VAR_TABLE.insert(f.arg_syms[n].clone(), Box::new(iter_arg));
-                }
-
-                // execute function
-                let mut result: Box<Ctr>;
-                let iterate = &*(f.ast);
-                loop {
-                    if let Ctr::Seg(ref data) = *iterate.car {
-                        match eval(data, self.loose_syms, true) {
-                            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!"),
-                    }
-                }
-
-                // clear local vars and restore previous values
-                for n in 0..f.arg_syms.len() {
-                    VAR_TABLE.remove(f.arg_syms[n]);
-                    if let Some(val) = holding_table.get(f.arg_syms[n]) {
-                        VAR_TABLE.insert(f.arg_syms[n].clone(), val);
-                    }
-                }
-
-                return Ok(result);
-            }
-        }
-    }
-}
-
-
-// the stdlib var export function with env_sync on
-lazy_static! {
-    pub static ref LIB_EXPORT_ENV: Function = Function {
-        name: String::from("export"),
-        loose_syms: true,
-        eval_lazy: true,
-        args: Args::Lazy(2),
-        function: Operation::Internal(Box::new( move |ast: &Seg| -> Ctr {
-                _export_callback(ast, true)
-            },
-        )),
-    };
-}
-
-// the stdlib var export function with env_sync off
-lazy_static! {
-    pub static ref LIB_EXPORT_NO_ENV: Function = Function {
-        name: String::from("export"),
-        loose_syms: true,
-        eval_lazy: true,
-        args: Args::Lazy(2),
-        function: Operation::Internal(Box::new( move |ast: &Seg| -> Ctr {
-                _export_callback(ast, false)
-            },
-        )),
-    };
-}
-
-
-fn _export_callback<'a> (ast: &Seg, env_cfg: bool) -> Ctr<'a> {
-    if let Ctr::Symbol(ref identifier) = *ast.car {
-        match &*ast.cdr {
-            Ctr::Seg(data_tree) => match eval(&Box::new(data_tree), false, true) {
-                Ok(seg) => match *seg {
-                    Ctr::Seg(val) => {
-                        SYM_TABLE.declare(Symbol {
-                            value: UserVar(val.car),
-                            name: identifier.clone(),
-                        });
-                        if env_cfg {
-                            env::set_var(identifier.clone(), val.car.to_string())
-                        }
-                    },
-                    _ =>  eprintln!("impossible args to export"),
-                },
-                Err(e) =>  eprintln!("couldnt eval symbol: {}", e),
-            },
-            Ctr::None => {
-                VAR_TABLE.remove(identifier.to_string());
-                if env_cfg {
-                    env::remove_var(identifier.to_string());
-                }
-            },
-            _ =>  eprintln!("args not in standard form"),
-        }
-    } else {
-        eprintln!("first argument to export must be a symbol");
-    }
-    return Ctr::None;
-}