Readers

Light-weight text input file readers.

		type Reader
	Light-weight text input file reader. File access. Error messages. Temporary data.

		type Reader_Access
	Access types for instance variables.

Internal initialization and finalization

		procedure Initialize_Reader
	Initialize a newly created reader instance.
	Param  Type  Description access This  Reader'Class  Initialize this reader.

		procedure Initialize_Reader
	Initialize a newly created reader instance with a file to read.
	Param  Type  Description access This  Reader'Class  Initialize this reader. in Filename  String  Open this file for reading.

		procedure Finalize_Reader
	Close the input file.
	Param  Type  Description access This  Reader'Class  Finalize this reader.

Creating readers

		function Current_Input
	Create a reader for current input (stdin).
	Param  Type  Description return  Reader_Access  The newly created reader instance.

		function Open
	Create a reader for file input.
	Param  Type  Description in Filename  String  Open this file. return  Reader_Access  The newly created reader instance.

		procedure Close
	Close a reader's input file.
	Param  Type  Description in out This  Reader_Access  Close this reader.

Wrappers for file input

		function End_Of_Line
	Check for end of line.
	Param  Type  Description access This  Reader'Class  Check EOL on this reader. return  Boolean  End of line reached?

		function End_Of_File
	Check if the end of the input file has been reached.
	Param  Type  Description access This  Reader'Class  Check EOF on this reader. return  Boolean  End of input file?

		procedure Get
	Get the next input character into This.C.
	Param  Type  Description access This  Reader'Class  Get character for this reader.

Error handling

		exception Syntax_Error
	The input syntax has been violated.

		procedure Error
	Print an error message, then raise Syntax_Error.
	Param  Type  Description access This  Reader'Class  Print error about this reader. in Message  String  Print this message.

		function "/"
	Concatenate two strings in a special format acceptable for expectation errors.
	Param  Type  Description in A, B  String  Join these strings. return  String  The combination with some joining text.

		procedure Expect_Error
	Print a formatted error message for unmatched expectations, then raise Syntax_Error.
	Param  Type  Description access This  Reader'Class  Print error about this reader. in Found  String  But this text was found. in Choices  String  This text was expected.

Reading characters

		function Get_Char
	Read the current character.
	Param  Type  Description access This  Reader'Class  Use this reader. return  Character  The character that was read.

		function Found_Char
	Check if a given token was found.
	Param  Type  Description access This  Reader'Class  Check character in this reader. in Char  Character  Check if this character was found. return  Boolean  True if the given character was found.

		procedure Assert_Char
	Test if the current look-ahead character is what we expect. Call Error if not, and that raises Syntax_Error.
	Param  Type  Description access This  Reader'Class  Check character in this reader. in Char  Character  Expect this character.