Using Perl 6 Custom Operators

Question

I study chemistry at the university and want to try writing textbook examples in Perl6 or Perl, for example, balancing a chemical formula or other processes!

Then I came across a problem related to the perl6 user-defined operator. I feel like I am repeating my code and myself when I use this function. It is hard to read and write. How can I simplify this?

#!/usr/bin/env perl6 use v6; #basic SI(International System of Units) type role MetricPrefix { method baseOn ( Str $base , Numeric $input ) { given $base { when 'pico' { return $input * 10**-12 } when 'namo' { return $input * 10**-9 } when 'micro' { return $input * 10**-6} when 'milli' { return $input * 10**-3 } when 'centi' { return $input * 10**-2 } when 'hecto' { return $input * 10**2 } when 'kilo' { return $input * 10**3 } when 'mega' { return $input * 10**6 } when 'giga' { return $input * 10**9 } when 'tera' { return $input * 10**12 } default { fail "you must input a metric prefix which allow pico to tera" } } } } class Mass does MetricPrefix { #basic Mass is g is different form si statda has $.g; submethod BUILD ( :$!g ) { } } class Length does MetricPrefix { has $.Length ; submethod BUILD ( :$!Length ) { } } multi postfix:<(kg)>( $input ) { return Mass.new( g => Mass.baseOn("kilo",$input) ) or fail "you Must input a number"; } multi postfix:<(g)>( $input ) { return Mass.new( g => $input ) or fail "you Must input a number"; } multi infix:<+>( Mass $inputOne , Mass $inputTwo ) is assoc<right> { return Mass.new( g => $inputOne.g + $inputTwo.g) or fail "error in there "; } multi infix:<->( Mass $inputOne , Mass $inputTwo ) is assoc<right> { return Mass.new( g => $inputOne.g - $inputTwo.g) or fail "error in there "; } multi infix:<*>( Mass $inputOne , Mass $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) is tighter( &infix:</>) { return Mass.new( g => $inputOne.g * $inputTwo.g) or fail "error in there "; } multi infix:</>( Mass $inputOne , Mass $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) { return Mass.new( g => $inputOne.g / $inputTwo.g) or fail "error in there "; } #the meterLeng multi postfix:<(km)>( $input ) { return Length.new( Length => Length.baseOn("kilo",$input) ) or fail "you Must input a number"; } multi postfix:<(m)>( $input ) { return Length.new( Length => $input ) or fail "you Must input a number"; } multi infix:<+>( Length $inputOne , Length $inputTwo ) is assoc<right> { return Length.new( Length => $inputOne.Length + $inputTwo.Length) or fail "error in there "; } multi infix:<->( Length $inputOne , Length $inputTwo ) is assoc<right> { return Length.new( Length => $inputOne.Length - $inputTwo.Length) or fail "error in there "; } multi infix:<*>( Length $inputOne , Length $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) is tighter( &infix:</>) { return Length.new( Length => $inputOne.Length * $inputTwo.Length) or fail "error in there "; } multi infix:</>( Length $inputOne , Length $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) { return Length.new( Length => $inputOne.Length / $inputTwo.Length) or fail "error in there "; } #just a test say 10(kg) + 1(g); say 10(m) + 1(m); 

Answer 1

I replaced the input type error messages. This will allow Perl 6 to worry about whether numbers are being entered and to give appropriate error messages if they are not. I also built on the assumption that all lengths and masses are positive.

 #!/usr/bin/env perl6 use v6; #basic SI(International System of Units) type role MetricPrefix { method baseOn ( Str $base , Numeric $input ) { given $base { when 'pico' { return $input * 10**-12 } when 'namo' { return $input * 10**-9 } when 'micro' { return $input * 10**-6 } when 'milli' { return $input * 10**-3 } when 'centi' { return $input * 10**-2 } when 'hecto' { return $input * 10**2 } when 'kilo' { return $input * 10**3 } when 'mega' { return $input * 10**6 } when 'giga' { return $input * 10**9 } when 'tera' { return $input * 10**12 } default { fail "you must input a metric prefix within the range of pico to tera" } } } } class Mass does MetricPrefix { #basic Mass is g is different form si statda has $.g where * > 0; } class Length does MetricPrefix { has $.Length where * > 0; } # Mass multi postfix:<(kg)>( $input where * > 0) { return Mass.new( g => Mass.baseOn("kilo",$input) ); } multi postfix:<(g)>( $input where * > 0) { return Mass.new( g => $input ); } multi infix:<+>( Mass $inputOne , Mass $inputTwo ) is assoc<right> { return Mass.new( g => $inputOne.g + $inputTwo.g); } multi infix:<->( Mass $inputOne , Mass $inputTwo ) is assoc<right> { return Mass.new( g => $inputOne.g - $inputTwo.g); } multi infix:<*>( Mass $inputOne , Mass $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) is tighter( &infix:</>) { return Mass.new( g => $inputOne.g * $inputTwo.g); } multi infix:</>( Mass $inputOne , Mass $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) { return Mass.new( g => $inputOne.g / $inputTwo.g); } #Length multi postfix:<(km)>( $input where * > 0) { return Length.new( Length => Length.baseOn("kilo",$input) ); } multi postfix:<(m)>( $input where * > 0) { return Length.new( Length => $input ); } multi infix:<+>( Length $inputOne , Length $inputTwo ) is assoc<right> { return Length.new( Length => $inputOne.Length + $inputTwo.Length); } multi infix:<->( Length $inputOne , Length $inputTwo ) is assoc<right> { return Length.new( Length => $inputOne.Length - $inputTwo.Length); } multi infix:<*>( Length $inputOne , Length $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) is tighter( &infix:</>) { return Length.new( Length => $inputOne.Length * $inputTwo.Length); } multi infix:</>( Length $inputOne , Length $inputTwo ) is assoc<right> is tighter( &infix:<+> ) is tighter( &infix:<-> ) { return Length.new( Length => $inputOne.Length / $inputTwo.Length); } #just a test say 10(kg) + 1(g); say 10(m) + 1(m);