streamParser {qmrparser}

Generic interface for character processing, allowing forward and backwards translation.

Description

Generic interface for character processing. It allows going forward sequentially or backwards to a previous arbitrary position.

Each one of these functions performs an operation on or obtains information from a character sequence (stream).

Usage

streamParserNextChar(stream)
streamParserNextCharSeq(stream)
streamParserPosition(stream)
streamParserClose(stream)

Arguments

stream

object containing information about the text to be processed and, specifically, about the next character to be read

Details

• streamParserNextChar

  Reads next character, checking if position to be read is correct.

• streamParserNextCharSeq

  Reads next character, without checking if position to be read is correct. Implemented since it is faster than streamParserNextChar

• streamParserPosition

  Returns information about text position being read.

• streamParserClose

  Closes the stream

Value

streamParserNextChar and streamParserNextCharSeq

Three field list:

• status

  "ok" or "eof"

• char

  Character read (ok) or "" (eof)

• stream

  With information about next character to be read or same position if end of file has been reached ("eof")

streamParserPosition

Three field list:

• fileName File name or "" if the stream is not associated with a file name

• line

  line number

• linePos

  character to be read position within its line

• streamPos

  character to be read position from the text beginning

streamParserClose

NULL

See Also

streamParserFromFileName streamParserFromString

Examples

stream<- streamParserFromString("Hello world")

cstream <- streamParserNextChar(stream)

while( cstream$status == "ok" ) {
    print(streamParserPosition(cstream$stream))
    print(cstream$char)
    cstream <- streamParserNextCharSeq(cstream$stream)
}

streamParserClose(stream)