[pure-lang-svn] SF.net SVN: pure-lang: [146] pure/trunk

[<ag...@us...>]

Revision: 146
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=146&view=rev
Author:   agraef
Date:     2008-05-27 12:17:52 -0700 (Tue, 27 May 2008)

Log Message:
-----------
Get rid of silly empty_list exceptions.

Modified Paths:
--------------
    pure/trunk/lib/prelude.pure
    pure/trunk/test/prelude.log

Modified: pure/trunk/lib/prelude.pure
===================================================================
--- pure/trunk/lib/prelude.pure	2008-05-27 18:13:58 UTC (rev 145)
+++ pure/trunk/lib/prelude.pure	2008-05-27 19:17:52 UTC (rev 146)
@@ -35,7 +35,6 @@
    need to work from the end of a list towards its front. */
 
 nullary    out_of_bounds;	// tuple or list index is out of bounds (!)
-nullary    empty_list;		// empty list (head, tail, etc.)
 //         bad_list_value xs;	// not a proper list value (reverse, etc.)
 				// xs denotes the offending tail of the list
 
@@ -256,7 +255,6 @@
 foldr1 f (x:xs)	= foldr f x xs;
 
 head (x:xs)	= x;
-head []		= throw empty_list;
 
 init [x]	= [];
 init (x:xs)	= accum [x] xs with
@@ -264,11 +262,9 @@
 		    accum ys (x:xs)	= accum (x:ys) xs;
 		    accum ys xs		= reverse ys+init xs;
 		  end;
-init []		= throw empty_list;
 
 last [x]	= x;
 last (x:xs)	= last xs;
-last []		= throw empty_list;
 
 map f []	= [];
 map f (x:xs)	= accum [f x] xs with
@@ -307,7 +303,6 @@
 		  end;
 
 tail (x:xs)	= xs;
-tail []		= throw empty_list;
 
 take n::int []	= [];
 take n::int (x:xs)

Modified: pure/trunk/test/prelude.log
===================================================================
--- pure/trunk/test/prelude.log	2008-05-27 18:13:58 UTC (rev 145)
+++ pure/trunk/test/prelude.log	2008-05-27 19:17:52 UTC (rev 146)
@@ -708,7 +708,6 @@
 foldr1 f/*0:01*/ [x/*0:101*/] = x/*0:101*/;
 foldr1 f/*0:01*/ (x/*0:101*/:xs/*0:11*/) = foldr f/*0:01*/ x/*0:101*/ xs/*0:11*/;
 head (x/*0:101*/:xs/*0:11*/) = x/*0:101*/;
-head [] = throw empty_list;
 init [x/*0:101*/] = [];
 init (x/*0:101*/:xs/*0:11*/) = accum/*0*/ [x/*0:101*/] xs/*0:11*/ with accum ys/*0:01*/ [] = reverse ys/*0:01*/; accum ys/*0:01*/ (x/*0:101*/:xs/*0:11*/) = accum/*1*/ (x/*0:101*/:ys/*0:01*/) xs/*0:11*/; accum ys/*0:01*/ xs/*0:1*/ = reverse ys/*0:01*/+init xs/*0:1*/ {
   rule #0: accum ys [] = reverse ys
@@ -742,10 +741,8 @@
 	<var> state 13
   state 13: #1 #2
 } end;
-init [] = throw empty_list;
 last [x/*0:101*/] = x/*0:101*/;
 last (x/*0:101*/:xs/*0:11*/) = last xs/*0:11*/;
-last [] = throw empty_list;
 map f/*0:01*/ [] = [];
 map f/*0:01*/ (x/*0:101*/:xs/*0:11*/) = accum/*0*/ [f/*0:01*/ x/*0:101*/] xs/*0:11*/ with accum ys/*0:01*/ [] = reverse ys/*0:01*/; accum ys/*0:01*/ (x/*0:101*/:xs/*0:11*/) = accum/*1*/ (f/*1:01*/ x/*0:101*/:ys/*0:01*/) xs/*0:11*/; accum ys/*0:01*/ xs/*0:1*/ = reverse ys/*0:01*/+map f/*1:01*/ xs/*0:1*/ {
   rule #0: accum ys [] = reverse ys
@@ -891,7 +888,6 @@
   state 1: #0
 } end;
 tail (x/*0:101*/:xs/*0:11*/) = xs/*0:11*/;
-tail [] = throw empty_list;
 take n/*0:01*/::int [] = [];
 take n/*0:01*/::int (x/*0:101*/:xs/*0:11*/) = accum/*0*/ n/*0:01*/ [] (x/*0:101*/:xs/*0:11*/) with accum _/*0:001*/ ys/*0:01*/ [] = reverse ys/*0:01*/; accum n/*0:001*/::int ys/*0:01*/ _/*0:1*/ = reverse ys/*0:01*/ if n/*0:001*/<=0; accum n/*0:001*/::int ys/*0:01*/ (x/*0:101*/:xs/*0:11*/) = accum/*1*/ (n/*0:001*/-1) (x/*0:101*/:ys/*0:01*/) xs/*0:11*/; accum n/*0:001*/ ys/*0:01*/ xs/*0:1*/ = reverse ys/*0:01*/+take n/*0:001*/ xs/*0:1*/ {
   rule #0: accum _ ys [] = reverse ys


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