Class: Antelope::Ace::Scanner

Inherits:
Object
  • Object
show all
Includes:
First, Second, Third
Defined in:
lib/antelope/ace/scanner.rb,
lib/antelope/ace/scanner/first.rb,
lib/antelope/ace/scanner/third.rb,
lib/antelope/ace/scanner/second.rb

Overview

Scans a given input. The input should be a properly formatted ACE file; see the Ace module for more information. This scanner uses the StringScanner class internally; see the ruby documentation for more on that. This scanner seperates scanning into three seperate stages: First, Second, and Third, for each section of the file, respectively.

See Also:

Defined Under Namespace

Modules: First, Second, Third

Constant Summary collapse

CONTENT_BOUNDRY =

The boundry between each section. Placed here to be easily modifiable. MUST be a regular expression.

/%%/
VALUE =

The value regular expression. It should match values; for example, things quoted in strings or word letters without quotes. Must respond to #to_s, since it is embedded within other regular expressions. The regular expression should place the contents of the value in the groups 2 or 3.

%q{(?:
    (?:("|')((?:\\\\|\\"|\\'|.)+?)\\1)
  | ([[:word:]]+)
)}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Third

#scan_third_part

Methods included from Second

#_scan_block, #scan_second_part, #scan_second_rule, #scan_second_rule_block, #scan_second_rule_body, #scan_second_rule_label, #scan_second_rule_or, #scan_second_rule_part, #scan_second_rule_prec

Methods included from First

#scan_first_copy, #scan_first_directive, #scan_first_part

Constructor Details

#initialize(input) ⇒ Scanner

Initialize the scanner with the input.



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# File 'lib/antelope/ace/scanner.rb', line 64

def initialize(input)
  @scanner = StringScanner.new(input)
  @tokens  = []
end

Instance Attribute Details

#scanner ⇒ StringScanner (readonly)

The string scanner that we're using to scan the string with.



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# File 'lib/antelope/ace/scanner.rb', line 26

def scanner
  @scanner
end

#tokens ⇒ Array<Array<(Symbol, Object, ...)>> (readonly)

An array of the tokens that the scanner scanned.



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# File 'lib/antelope/ace/scanner.rb', line 31

def tokens
  @tokens
end

Class Method Details

.scan(source) ⇒ Array<Array<(Symbol, Object, ...)>>

Scans a file. It returns the tokens resulting from scanning.

See Also:



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# File 'lib/antelope/ace/scanner.rb', line 57

def self.scan(source)
  new(source).scan_file
end

Instance Method Details

#error! ⇒ void (private)

This method returns an undefined value.

Raises an error; first creates a small snippet to give the developer some context.

Raises:



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# File 'lib/antelope/ace/scanner.rb', line 101

def error!
  start = [@scanner.pos - 8, 0].max
  stop  = [@scanner.pos + 8, @scanner.string.length].min
  snip  = @scanner.string[start..stop].strip
  char  = @scanner.string[@scanner.pos]
  raise SyntaxError, "invalid syntax near `#{snip.inspect}' (#{char.inspect})"
end

#scan_file ⇒ Array<Array<(Symbol, Object, ...)>>

Scans the file in parts.

Raises:

  • (SyntaxError) —

    if the source is malformed in some way.

See Also:



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# File 'lib/antelope/ace/scanner.rb', line 78

def scan_file
  scan_first_part
  scan_second_part
  scan_third_part
  tokens
end

#scan_whitespace ⇒ Boolean

Scans for whitespace. If the next character is whitespace, it will consume all whitespace until the next non-whitespace character.



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# File 'lib/antelope/ace/scanner.rb', line 90

def scan_whitespace
  @scanner.scan(/\s+/)
end