Add support for relative and absolute errors in comparing floats

Author: nomennescio

test/test-float-equality.4th

@@ -0,0 +1,34 @@
+\ Copyright 2023 nomennescio
+
+\ pass
+<{ 1e -> 1e }>
+\ fail
+<{ 1.001e -> 1e }>
+
+\ abs<> ( f1 f2 -- ? ) := |f1-f2| > epsilon
+F<>: abs<>
+0.01e epsilon f!
+\ pass
+<{ 1.001e -> 1e }>
+\ fail
+<{ 1.1e -> 1e }>
+1e epsilon f!
+\ pass
+<{ 1.1e -> 1e }>
+
+\ rel<> ( f1 f2 -- ? ) := |f1-f2|/|f1+f2| > epsilon
+F<>: rel<>
+0.05e epsilon f!
+\ pass
+<{ 5.5e -> 5e }>
+<{ 11e -> 10e }>
+\ fail
+<{ 5.6e -> 5e }>
+<{ 11.2e -> 10e }>
+
+\ f<> ( f1 f2 -- ? ) := f1 <> f2
+F<>: f<>
+\ pass
+<{ 1e -> 1e }>
+\ fail
+<{ 1.001e -> 1e }>

test/test-float-equality.expected

@@ -0,0 +1,22 @@
+
+<PASSED::>Test Passed
+
+<FAILED::>Expected 1. , got 1.001 
+
+<PASSED::>Test Passed
+
+<FAILED::>Expected 1. , got 1.1 
+
+<PASSED::>Test Passed
+
+<PASSED::>Test Passed
+
+<PASSED::>Test Passed
+
+<FAILED::>Expected 5. , got 5.6 
+
+<FAILED::>Expected 10. , got 11.2 
+
+<PASSED::>Test Passed
+
+<FAILED::>Expected 1. , got 1.001 

testest.4th

@@ -70,8 +70,16 @@ variable ^#results.f  ' #results.f$  ^#results.f !
 
 : -> depth start-depth @ - dup #actuals ! actuals[] fdepth start-fdepth @ - dup #actuals.f ! actuals.f[] store-stacks ;
 
+variable ^f<>
+: F<>: ' ^f<> ! ;
+F<>: f<>
+
+fvariable epsilon
+: rel<> epsilon f@ f~rel 0= ;
+: abs<> epsilon f@ f~abs 0= ;
+
 : compare   { e* a* d -- d' }  e*  @ a*  @  <> d + ;
-: compare.f { e* a* d -- d' }  e* f@ a* f@ f<> d + ;
+: compare.f { e* a* d -- d' }  e* f@ a* f@ ^f<> @ ^ d + ;
 
 : compare-results { #e e* #a a* s 'cmp } ( #p #f #r -- #p' #f' #r' )
   #e #a = if