Raku Books / Creating a Compiler in Raku / A Better Translator
Sophisticated numbers
The translator works with numbers, which we already can parse really well. Let us join the two grammars and let the translator work with all kind of numbers, positive, negative, integers, floating-point and numbers in scientific notation.
Take the body of the Number grammar from Chapter 2 and
copy it to the grammar of Lingua. The TOP rule of
Number should become the value rule in
Lingua.
token value {
<sign>? [
| <integer>
| <floating-point>
] <exponent>?
}Also do not forget to update the actions class:
method value($/) {
$/.make(+$/);
}Try the following program now:
my alpha;
my beta;
my gamma;
alpha = 3.14;
beta = 42;
gamma = -4.5E-2;
say alpha;
say beta;
say gamma;It should parse the numbers and print them all. This step is fully completed now.