grammar,compiler: Add Support For Fixed-Width Integers

Distinguishing between signed and unsigned fixed-width integer
types must still be done.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

tree-sitter-p4/grammar.js

@@ -40,9 +40,12 @@ export default grammar({
 
         // Common - Types
         typeRef: $ => choice($.baseType, $.type_identifier),
-        baseType: $ => choice($.bool, $.error, $.string, $.int, $.bit /* omitting "templated" types" */),
+        baseType: $ => choice($.bool, $.error, $.string, $.int_type, $.bit /* omitting "templated" types" */),
         constructor_parameters: $ => seq('(', optional($.parameter_list), ')'),
 
+        int_type: $ => seq($.int, optional($.bit_width)),
+        bit_width: $ => seq('<', $.integer, '>'),
+
         // Common - Parsers
         parserType: $ => seq(optional($.annotations), $.parser, field('parser_name', $.identifier), optional($.typeParameters), $.parameters),
 
@@ -120,7 +123,7 @@ export default grammar({
         // Expressions
         expression: $ => choice($.grouped_expression, $.simple_expression),
         grouped_expression: $ => seq('(', $.expression, ')'),
-        simple_expression: $ => choice($.identifier, $.integer, $.booleanLiteralExpression, $.string_literal, $.binaryOperatorExpression, $.arrayAccessExpression, $.fieldAccessExpression, $.function_call), // Very limited.
+        simple_expression: $ => choice($.identifier, $.integer, $.integer_elaborated, $.booleanLiteralExpression, $.string_literal, $.binaryOperatorExpression, $.arrayAccessExpression, $.fieldAccessExpression, $.function_call), // Very limited.
         booleanLiteralExpression: $ => choice($.true, $.false),
         selectExpression: $ => seq($.select, '(', $.expression, ')', '{', $.selectBody, '}'), // TODO: Should be expression list and not just a single expression
         transitionSelectionExpression: $ => choice($.identifier, $.selectExpression),
@@ -211,6 +214,7 @@ export default grammar({
         type_identifier: $ => /[A-Za-z_]+/,
         string_literal: $ => /"[^"]*"/,
         integer: $ => /[0-9]+/,
+        integer_elaborated: $ => /[0-9]+[ws][-0-9]+/,
         annotation_literal: $ => /@[A-Za-z_]+/,
         default_keyset: $=> '_',