From: Tim Vaughan <tgvaughan@gmail.com>
Date: Tue, 26 Apr 2016 09:58:42 +0000 (+1200)
Subject: Added MAX and MIN
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=commitdiff_plain;h=aa56183a78faf9a661146353446af24fae716d92;p=forth.jl.git

Added MAX and MIN
---

diff --git a/src/forth.jl b/src/forth.jl
index 11d0044..9c3f62e 100644
--- a/src/forth.jl
+++ b/src/forth.jl
@@ -844,6 +844,11 @@ EXECUTE = defPrimWord("EXECUTE", () -> begin
     return mem[reg.W]
 end)
 
+type ParseError <: Exception
+    wordName::ASCIIString
+end
+Base.showerror(io::IO, ex::ParseError) = print(io, "Parse error at word: '$(ex.wordName)'.")
+
 INTERPRET = defPrimWord("INTERPRET", () -> begin
 
     callPrim(mem[WORD])
@@ -881,8 +886,7 @@ INTERPRET = defPrimWord("INTERPRET", () -> begin
         callPrim(mem[NUMBER])
 
         if popPS() != 0
-            println("Parse error at word: '$wordName'")
-            return NEXT
+            throw(ParseError(wordName))
         end
 
         if mem[STATE] == 0
@@ -979,7 +983,7 @@ function run(;initialize=true)
     global initialized, initFileName
     if !initialized && initialize
         if initFileName != nothing
-            print("Including definitions from $initFileName.")
+            print("Including definitions from $initFileName...")
             push!(sources, open(initFileName, "r"))
             initialized = true
         else
@@ -1002,6 +1006,11 @@ function run(;initialize=true)
             showerror(STDOUT, ex)
             println()
 
+            while !isempty(sources) && currentSource() != STDIN
+                close(pop!(sources))
+            end
+
+            mem[STATE] = 0
             mem[NUMTIB] = 0
             reg.IP = QUIT + 1
             jmp = NEXT
diff --git a/src/lib.4th b/src/lib.4th
index f4e9908..ae4e60e 100644
--- a/src/lib.4th
+++ b/src/lib.4th
@@ -2,13 +2,7 @@
 : MOD /MOD DROP ;
 : */ * / ;
 
-: '\n' 10 ;
-: BL 32 ;
-
-: CR '\n' emit ;
-: SPACE BL emit ;
-
-: NEGATE 0 swap - ;
+: NEGATE 0 SWAP - ;
 
 : TRUE -1 ;
 : FALSE 0 ;
@@ -18,6 +12,9 @@
 
 : DEPTH PSP@ PSP0 @ - ;
 
+: '\n' 10 ;
+: BL 32 ;
+
 : LITERAL IMMEDIATE ' LIT , , ;
 
 : ':' [ CHAR : ] LITERAL ;
@@ -32,6 +29,9 @@
 : '-' [ CHAR - ] LITERAL ;
 : '.' [ CHAR . ] LITERAL ;
 
+: CR '\n' emit ;
+: SPACE BL emit ;
+
 : [COMPILE] IMMEDIATE
         WORD            \ get the next word
         FIND            \ find it in the dictionary
@@ -170,12 +170,28 @@
 : HEX ( -- ) 16 BASE ! ;
 
 ( Compute absolute value. )
-: ABS           ( n -- m)
+: ABS           ( n -- |n| )
         dup 0< if
                 negate
         then
 ;
 
+: MAX           ( n m -- max )
+        2dup - 0< if
+                swap drop
+        else
+                drop
+        then
+;
+
+: MIN           ( n m -- max )
+        2dup - 0> if
+                swap drop
+        else
+                drop
+        then
+;
+
 ( PRINTING NUMBERS ---------------------------------------------------------------------- )
 
 ( This is the underlying recursive definition of U. )