From c0687799ec28b838f1d086e3a6798ba6fa9f8fa4 Mon Sep 17 00:00:00 2001
From: psf <psf@phone>
Date: Sun, 27 Mar 2022 21:17:01 -0700
Subject: [PATCH] variable, constant, forget

---
 frustration.rs | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/frustration.rs b/frustration.rs
index 3346f20..bf1cbcd 100644
--- a/frustration.rs
+++ b/frustration.rs
@@ -56,7 +56,7 @@ struct TableEntry {
     immediate: bool
 }
 
-const PRIMITIVES: [TableEntry; 27] = [
+const PRIMITIVES: [TableEntry; 31] = [
     TableEntry {f: ret     , name: None, immediate: false},
     TableEntry {f: lit     , name: None, immediate: false},
     TableEntry {f: add     , name: Some(ShortName {bytes: *b"+  ", length: 1}), immediate: false},
@@ -65,12 +65,16 @@ const PRIMITIVES: [TableEntry; 27] = [
     TableEntry {f: create_d, name: Some(ShortName {bytes: *b"cre", length: 6}), immediate: false},
     TableEntry {f: div     , name: Some(ShortName {bytes: *b"/  ", length: 1}), immediate: false},
     TableEntry {f: dot     , name: Some(ShortName {bytes: *b".  ", length: 1}), immediate: false},
+    TableEntry {f: dots    , name: Some(ShortName {bytes: *b".s ", length: 2}), immediate: false},
     TableEntry {f: drop    , name: Some(ShortName {bytes: *b"dro", length: 4}), immediate: false},
     TableEntry {f: dup     , name: Some(ShortName {bytes: *b"dup", length: 3}), immediate: false},
     TableEntry {f: dump    , name: Some(ShortName {bytes: *b"dum", length: 4}), immediate: false},
+    TableEntry {f: forget  , name: Some(ShortName {bytes: *b"for", length: 6}), immediate: false},
     TableEntry {f: from_r_d, name: Some(ShortName {bytes: *b"r> ", length: 2}), immediate: false},
+    TableEntry {f: here    , name: Some(ShortName {bytes: *b"her", length: 4}), immediate: false},
     TableEntry {f: if_skip  ,name: Some(ShortName {bytes: *b"?  ", length: 1}), immediate: false},
     TableEntry {f: immediate,name: Some(ShortName {bytes: *b"imm", length: 9}), immediate: false},
+    TableEntry {f: latest  , name: Some(ShortName {bytes: *b"lat", length: 6}), immediate: false},
     TableEntry {f: lbracket, name: Some(ShortName {bytes: *b"[  ", length: 1}), immediate: true},
     TableEntry {f: load    , name: Some(ShortName {bytes: *b"@  ", length: 1}), immediate: false},
     TableEntry {f: mul     , name: Some(ShortName {bytes: *b"*  ", length: 1}), immediate: false},
@@ -96,9 +100,12 @@ fn new_core() -> Core {
     init_dictionary(&mut c);
 
     let autoexec = [
-        "create : ] create smudge ] [ 65535 ,",
-        "create ; ] unsmudge 65535 , [ ' [ , 65535 , immediate",
-        ": recursive  unsmudge ; immediate"
+        "create :  ] create smudge ] [ 65535 ,",
+        "create ;  ] unsmudge 65535 , [ ' [ , 65535 , immediate",
+        ": recursive  unsmudge ; immediate",
+        ": literal  65534 , , ; immediate",
+        ": constant  create [ ' literal , ] [ ' ret ] literal , ;",
+        ": variable  create  here 6 +  [ ' literal , ]  [ ' ret ] literal , 0 , ;"
     ];
 
     for s in autoexec {
@@ -227,6 +234,13 @@ fn load(c: &mut Core) {
     push(c, u16::from_le_bytes(c.ram[addr..=addr+1].try_into().unwrap()));
 }
 
+fn forget(c: &mut Core) {
+    let xt = pop(c);
+    c.here = xt - 6;
+    let i = c.here as usize;
+    c.dp = u16::from_le_bytes(c.ram[i..=i+1].try_into().unwrap());
+}
+
 // --- Stack management ---
 
 fn push(c: &mut Core, val: u16) {
@@ -316,6 +330,12 @@ fn dot(c: &mut Core) {
     print!("{} ", pop(c));
 }
 
+fn dots(c: &mut Core) {
+    for i in &c.dstack[0..c.tds] {
+        print!("{} ", i);
+    }
+}
+
 fn dump(c: &mut Core) {
     println!("{:?}", c);
 }
@@ -363,7 +383,6 @@ fn div(c: &mut Core) {
     push(c, v2.saturating_div(v1));
 }
 
-
 // --- Inner interpreter ---
 
 fn fetch(c: &mut Core) -> u16 {
@@ -409,6 +428,14 @@ fn rbracket(c: &mut Core) {
     c.state = State::Compiling;
 }
 
+fn latest(c: &mut Core) {
+    push(c, c.dp);
+}
+
+fn here(c: &mut Core) {
+    push(c, c.here);
+}
+
 fn outer(c: &mut Core, s: &str) {
     let ss = s.trim();
     let mut tokens = ss.split(" ").peekable();