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$Id: Lexer_Ops.lhs,v 1.1 1996/01/08 20:17:58 partain Exp $
>module Lexer_Ops where
>import Lexer_Buffer(Lexer_Buffer, add, empty, flush, len, to_string)
> renaming
> (add to add_char, empty to empty_buffer, to_string to buffer_to_string)
>import Lexer_Combinators(and_with, return)
>import Lexer_State
> (Lexer_State,Lexer_Action(..),i_buffer,i_source_pos,p_buffer,p_source_pos)
>import Oberon_Id(Oberon_Id,from_string) renaming (from_string to string_to_id)
>import Oberon_Integer
> (Oberon_Integer, from_decimal_string, from_hex_string, from_int)
> renaming
> ( from_decimal_string to decimal_string_to_int
> , from_hex_string to hex_string_to_int
> )
>import Oberon_Real(Oberon_Real, from_string) renaming
> (from_string to string_to_real)
>import Oberon_String(Oberon_String, from_string) renaming
> (from_string to string_to_string)
>import Lexer_Combinators(and_then)
>import Source_Position(Source_Position, next_line, shift_column, start)
> renaming (start to start_position)
>t_source_pos transformer =
> p_source_pos `and_with` \pos ->
> i_source_pos (transformer pos)
>t_buffer transformer =
> p_buffer `and_with` \buff ->
> i_buffer (transformer buff)
>buffer_len :: Lexer_Action Int
>buffer_len =
> p_buffer `and_with` \buff ->
> return (len buff)
>decimal_to_int :: Lexer_Action Oberon_Integer
>decimal_to_int =
> p_buffer `and_with` \buff ->
> return (decimal_string_to_int (buffer_to_string buff))
>flush_buffer :: Lexer_Action ()
>flush_buffer = t_buffer flush
>hex_to_int :: Lexer_Action Oberon_Integer
>hex_to_int =
> p_buffer `and_with` \buff ->
> return (hex_string_to_int (buffer_to_string buff))
>move_input_column :: Int -> Lexer_Action ()
>move_input_column dist = t_source_pos (flip shift_column dist)
>next_input_line :: Lexer_Action ()
>next_input_line = t_source_pos next_line
>store_char :: Char -> Lexer_Action ()
>store_char c = t_buffer (add_char c)
>to_char :: Lexer_Action Oberon_Integer
>to_char =
> p_buffer `and_with` \buff ->
> return ((from_int . toInteger . ord . head . buffer_to_string) buff)
Converts the string in the buffer into a character (actually an
integer since characters are represented as integers). The
pre-condition is that there is exactly one character in the buffer
when this is called.
>to_id :: Lexer_Action Oberon_Id
>to_id =
> p_buffer `and_with` \buff ->
> return (string_to_id (buffer_to_string buff))
>to_real :: Lexer_Action Oberon_Real
>to_real =
> p_buffer `and_with` \buff ->
> return (string_to_real (buffer_to_string buff))
>to_string :: Lexer_Action Oberon_String
>to_string =
> p_buffer `and_with` \buff ->
> return (string_to_string (buffer_to_string buff))
% eof
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