transform first couple of grammar files

lib/parser/basic.citrus

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+
+grammar BasicTypes
+
+  # space really is just space. ruby is newline sensitive, so there is more whitespace footwork
+  # rule of thumb is that anything eats space behind it, but only space, no newlines
+  rule space  [ \t]*  end
+
+  rule linebreak "\n" end
+
+  rule comment
+    "#" (/.*/ !linebreak) linebreak
+  end
+
+  rule dot '.' end
+
+  ## Lexical syntax
+
+  rule number
+    float | integer
+  end
+
+  rule float
+    (digits '.' digits space*) { to_str.to_f }
+  end
+
+  rule integer
+    (digits space*) { to_str.to_i }
+  end
+
+  rule digits
+    [0-9]+ ('_' [0-9]+)* # Numbers may contain underscores.
+  end
+
+  rule lparen '(' space* end
+  rule rparen ')' space* end
+
+
+  # Hierarchical syntax
+
+  rule term
+    additive | factor
+  end
+
+  rule additive
+    (factor operator:('+' | '-') space* term) {
+      capture(:factor).value.send(capture(:operator).to_s, capture(:term).value)
+    }
+  end
+
+  rule factor
+    multiplicative | prefix
+  end
+
+  rule multiplicative
+    (prefix operator:('*' | '/' | '%') space* factor) {
+      capture(:prefix).value.send(capture(:operator).to_s, capture(:factor).value)
+    }
+  end
+
+  rule prefix
+    prefixed | exponent
+  end
+
+  rule prefixed
+    (operator:('-' | '+' | '~') space* prefix) {
+      s = capture(:operator).to_s
+      s += '@' unless s == '~' # Unary + and - require an @.
+      capture(:prefix).value.send(s)
+    }
+  end
+
+  rule exponent
+    exponential | primary
+  end
+
+  rule exponential
+    (primary operator:'**' space* prefix) {
+      capture(:primary).value.send(capture(:operator).to_s, capture(:prefix).value)
+    }
+  end
+
+  rule primary
+    group | number
+  end
+
+  rule group
+    (lparen term rparen) {
+      capture(:term).value
+    }
+  end
+
+end

lib/parser/keywords.citrus

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+grammar Keywords
+  include BasicTypes
+
+  rule keyword_begin    'begin'  space? end
+  rule keyword_class    'class'  space?  end
+  rule keyword_def      'def'    space?  end
+  rule keyword_do       'do'     space? end
+  rule keyword_else     'else'   space?  end
+  rule keyword_end      'end'    space?  end
+  rule keyword_false    'false'  space? end
+  rule keyword_if       'if'     space?  end
+  rule keyword_rescue   'rescue' space? end
+  rule keyword_return   'return' space? end
+  rule keyword_module   'module' space?  end
+  rule keyword_nil      'nil'    space? end
+  rule keyword_unless   'unless' space? end
+  rule keyword_until    'until'  space? end
+  rule keyword_while    'while'  space? end
+
+  rule keyword_true
+    ('true'   space?) { Ast::TrueExpression.new }
+  end
+
+  # this rule is just to make sure identifiers can't be keywords. Kind of duplication here, but we need the
+  # space in above rules, so just make sure to add any here too.
+  rule keyword   ('begin'  |  'def'  |  'do'  |  'else'  |  'end'  |
+                   'false' |  'if' |  'rescue' |  'true' |  'nil'  |
+                   'unless' |  'until' |  'while') space?
+  end
+
+end