differentiate between TCL and IP. long answer.
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To understand the difference between command sets manipulating binary and string data you have to understand the distinction between these two kinds of data.
In Tcl, as in many (most?) high-level languages, strings are rather abstract — that is, they are described in pretty high-level terms. Particularly in Tcl, strings are defined to have the following properties:
They contain characters from the Unicoderepertoire.The Tcl runtime provides the set of standard commands to operate on strings — such as indexing, searching, appending to, extracting a substring etc.
Note that many things are left out from this definition:
The encoding in which these Unicode characters are stored.How exactly they are stored (NUL-terminated arrays? linked lists of unsigned longs? something else?).
(To put it into a more interesting perspective, Tcl is able to transparently change the underlying representations of strings it manages — between UTF-8 and UTF-16 encoded sequences. But here we're talking about the reference Tcl implementation, and other implementations (such as Jacl for instance) are free to do something else completely.)
The same approach is used to manipulate all the other kinds of data in the Tcl interpreter. Say, integer numbers are stored using native platform "integers" (roughly "as in C") but they are transparently upgraded into arbitrary sized integers if an arithmetic operation is about to overflow the platform-sized result.
So long as you don't leave the comfortable world of the Tcl interpreter, this is all you should know about the data types it manages. But now there's the outside world. In it, abstract concepts which are Tcl strings do not exist. Say, if you need to communicate to some other program over a network socket or by means of using a file or whatever other kind of media, you have to get down to the level of exact layouts of raw bytes which are described by "wire protocols" and file formats or whatever applies to your case. This is where "binaries" come into play: they allow you to precisely specify how the data is laid out so that it's ready to be transferred to the outside world or be consumed from it — binary format makes these "binaries" and binary scan reads them.
Note that certain Tcl commands for working with the outside world are "smart by default" — for instance, the open command which opens files by default assumes they are textual and are encoded in the default system encoding (which is deduced, broadly speaking, from the environment). You can then use the chan configure (of fconfigure — in older versions of Tcl) command to either change this encoding or completely inhibit conversions by specifying the channel is in "binary mode". The same applies to EOL conversions.
Note also that there are specialized packages for Tcl that effectively hide the complexities of working with a particular wire/file format. To present one example, the tdom package works with XML; when you manipulate XML using this package, you're not concerned with how exactly XML must be represented when, say, saved to a file — you just work with tdom's objects, native Tcl strings etc.
In Tcl, as in many (most?) high-level languages, strings are rather abstract — that is, they are described in pretty high-level terms. Particularly in Tcl, strings are defined to have the following properties:
They contain characters from the Unicoderepertoire.The Tcl runtime provides the set of standard commands to operate on strings — such as indexing, searching, appending to, extracting a substring etc.
Note that many things are left out from this definition:
The encoding in which these Unicode characters are stored.How exactly they are stored (NUL-terminated arrays? linked lists of unsigned longs? something else?).
(To put it into a more interesting perspective, Tcl is able to transparently change the underlying representations of strings it manages — between UTF-8 and UTF-16 encoded sequences. But here we're talking about the reference Tcl implementation, and other implementations (such as Jacl for instance) are free to do something else completely.)
The same approach is used to manipulate all the other kinds of data in the Tcl interpreter. Say, integer numbers are stored using native platform "integers" (roughly "as in C") but they are transparently upgraded into arbitrary sized integers if an arithmetic operation is about to overflow the platform-sized result.
So long as you don't leave the comfortable world of the Tcl interpreter, this is all you should know about the data types it manages. But now there's the outside world. In it, abstract concepts which are Tcl strings do not exist. Say, if you need to communicate to some other program over a network socket or by means of using a file or whatever other kind of media, you have to get down to the level of exact layouts of raw bytes which are described by "wire protocols" and file formats or whatever applies to your case. This is where "binaries" come into play: they allow you to precisely specify how the data is laid out so that it's ready to be transferred to the outside world or be consumed from it — binary format makes these "binaries" and binary scan reads them.
Note that certain Tcl commands for working with the outside world are "smart by default" — for instance, the open command which opens files by default assumes they are textual and are encoded in the default system encoding (which is deduced, broadly speaking, from the environment). You can then use the chan configure (of fconfigure — in older versions of Tcl) command to either change this encoding or completely inhibit conversions by specifying the channel is in "binary mode". The same applies to EOL conversions.
Note also that there are specialized packages for Tcl that effectively hide the complexities of working with a particular wire/file format. To present one example, the tdom package works with XML; when you manipulate XML using this package, you're not concerned with how exactly XML must be represented when, say, saved to a file — you just work with tdom's objects, native Tcl strings etc.
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