Description Usage Details Value See Also
Creating readers.
1 |
Readers are functions for extracting textual content and metadata out
of elements delivered by a Source
, and for constructing a
TextDocument
. A reader must accept following arguments in
its signature:
elem
a named list with the components content
and
uri
(as delivered by a Source
via
getElem
or pGetElem
).
language
a character string giving the language.
id
a character giving a unique identifier for the created text document.
The element elem
is typically provided by a source whereas the language
and the identifier are normally provided by a corpus constructor (for the case
that elem$content
does not give information on these two essential
items).
In case a reader expects configuration arguments we can use a function
generator. A function generator is indicated by inheriting from class
FunctionGenerator
and function
. It allows us to process
additional arguments, store them in an environment, return a reader function
with the well-defined signature described above, and still be able to access
the additional arguments via lexical scoping. All corpus constructors in
package tm check the reader function for being a function generator and
if so apply it to yield the reader with the expected signature.
For getReaders()
, a character vector with readers provided by package
tm.
readDOC
, readPDF
, readPlain
,
readRCV1
, readRCV1asPlain
,
readReut21578XML
, readReut21578XMLasPlain
,
and readXML
.
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