Release 2.6 (November 1997)

The following changes were made between release 2.5 and 2.6:

• The Tk widgets were bound to Glish in an integrated way (§ 10, page ), and the necessary functions were added:
  • have_gui( ), § 10.8, page 
  • tk_hold( ), § 10.8, page 
  • tk_release( ), § 10.8, page 
  • frame(...), § 10.1, page 
  • button(...), § 10.2, page 
  • scale(...), § 10.8, page 
  • text(...), § 10.11, page 
  • scrollbar(...), § 10.4.2, page 
  • label(...), § 10.7, page 
  • entry(...), § 10.10, page 
  • message(...), § 10.9, page 
  • listbox(...), § 10.6, page 
  • canvas(...), § 10.12, page 
• The Glish library libglish.a was split into libglishp.a and libglish.a so clients no longer must link in all of the interpreter's symbols (now in libglishp.a).
• Changed function scope rules. Now variables are local to the function by default (§ 6.6.1, page ).
• The Glish interpreter now does non-blocking writes for sending events. This allows the interpreter to send as much of an event as it can and then do other things until it can continue sending the event. This avoids some cases of deadlock, e.g. :

          echo_client->h(1:3000); echo_client->h(1:3000)

  This required changes in the transport layer.
• The transport layer (SDS) was replaced. The new library is called SOS (libsos.a). It is a minimal C++ reimplementation of the portion of SDS which Glish used. This new transport layer overcomes some of SDS' short comings:
  • coercion of type boolean to type integer in boolean values sent to clients
  • loss of ``embedded'' whitespace in strings sent to clients
  • lack of non-blocking write
  SOS does this without sacrificing speed. SOS uses writev( ) to minimize the number of system calls in sending data.

  This means that all clients compiled with earlier versions of the Glish libraries must be recompiled and relinked with these newer libraries.

• opaque values are no longer supported.
• Files written to disk with write_value() from an earlier version of Glish will not be readable via read_value() with this version of Glish. This is due to the change in transport layers.
• Changed string to boolean conversion; now a string is T if it has a non-zero length (§ 9.2, page ).
• Added <fail> values as a way to deal with error conditions (§ 8.1, page ).
• const now means not modifiable rather than ``constant reference'' (§ 3.9, page ).
• All value in Glish are now ``copy-on-write''. This means that ref function parameters should typically not be needed; val is now the default type for function parameters (§ 3.10, page ).
• Added numeric constants pi and e (§ 9.11, page ).
• Changed function parameter evaluation to permit things like:

          func foo( x, y=2*x ) { print y }

• Dropped the keywords ``send'' and ``request''. Currently these keywords are simply ignored, but with release 2.6.1 they will result in syntax errors (§ 7, page ).
• Many memory leaks were fixed. Currently the most notable outstanding leaks are the result of strdup( ) calls; the current String class needs to be beefed up and improved so it can be used throughout Glish instead of char*.
• Changed include from directive to a statement (§ 4.14, page ).
• Added eval( ) to allow strings to be interpreted as Glish programs (§ 9.7, page )
• Added several new predefined functions:
  • general purpose:
    • time( ), § 9.4, page 
    • is_nan(x), § 9.1, page 
    • is_modifiable(x), § 9.1, page 
    • is_const(x), § 9.1, page 
    • ceil(x), § 9.2.2, page 
    • floor(x), § 9.2.2, page 
    • is_fail(x), § 9.1, page 
  • array manipulation:
    • rbind(...), § 9.3, page 
    • cbind(...), § 9.3, page 
  • symbol table manipulation:
    • is_defined(x), § 9.6, page 
    • symbol_value(x), § 9.6, page 
    • symbol_names(...), § 9.6, page 
    • symbol_set(...), § 9.6, page 
    • symbol_delete(x), § 9.6, page 
  • event related:
    • whenever_active(x), § 9.10, page 
• Some functions were changed:
  • log is now log base 10, and a new function ln is the natural log (§ 9.3, page ).
  • split can now be used to split a string into individual characters by passing an empty separator string, e.g. split('this','') returns t h i s (§ 9.5, page ).
  • whenever_stmts added an extra field to the record returned. This field indicates which of the statements are active.
• Added wider keyword to access a scope which is wider than the current scope, but not global (§ 6.6.1, page ). The main reason this was added was to support function closures (§ 6.6.1, page ).
• With nested function definitions, the multiple scopes are preserved and used when the function is invoked. This along with wider allows for useful function closures (§ 6.6.1, page ).
• A couple of important changes were made to whenever statements:
  • ``stacked'' whenever statements (as a result of intervening awaits) are now handled properly. The event is matched with the oldest queued whenever statement (§ 7.6.2, page ).
  • Multiple function scope are now preserved and used if necessary. This is an issue when a whenever statement is set up within nested function definitions.
• ^C, ^\, and ^Z now work properly, at least when command line editing is enabled. ^C prompts before exiting; ^\ exits directly.
• Floating point exceptions are now handled properly on most platforms. This was especially a problem on the DEC Alpha machines.
• Added ``-l file'' command line parameter (§ 11.1, page ).
• Rewrote the glishd client (see § 14.2). It can now either be started by root and run as a daemon accepting connections on a published port, or it can be started by a user and only handle commands from that particular user. When glishd is started by root, users are authenticated using keys. Each user has a key, and each host has a key. glishd (running as root) authenticates each user using a combination of the host and user key. This authentication is done thanks to Vern's NPD library. Authentication is not necessary when glishd is started by a user other than root.
• Improved remote client start up. Now the binary search path and the dynamic loader search path are set properly before starting either the glishd or a client.
• The configuration and make system can now handle creating shared Glish libraries for most architectures.
• Now whenever Glish dies, it attempts to write out all of the non-function, non-agent values to a file called glish.core.
• Clients can now be shared by multiple Glish interpreters (see § 7.9 and § 14.3). This allows interpreters to communicate with each other. A pragma directive was added to allow script clients to specify that they should be shared. The following are the only valid pragmas for share clients are:
  • pragma shared user
  • pragma shared group
  • pragma shared world
  Much of the initial work on shared clients was done by Todd Satogata (satogata@bnl.gov) and Chris Saltmarsh (salty@farpoint.co.uk).
• Several new fields were added to the system record:
  • system.pid and system.ppid, § 9.11, page 
  • system.tk, § 10.8, page 
  • system.limits.max and system.limits.min, § 9.11, page 
  • system.path.include, § 4.14, page 
  • system.path.bin.hostname, § 7.8.1, page 
  • system.path.bin.default, § 7.8.1, page 
  • system.path.key, § 14.2.1, page 
  • system.print.limit, § 5.3.2, page 
  • system.print.precision, § 5.3.1, page 
  • system.output.trace, § 8.3, page 
  • system.output.log, system.output.ilog, and system.output.olog, § 8.2, page 
  • system.output.pager.exec, system.output.pager.limit, § 5.3, page 
  setting some of these affect things like how clients or include files are found, how variables are displayed, or if debug output is generated or not.
• Added paged output so that large values are sent through a pager, e.g. less or more, for display.
• Added handling for the escape sequences '\a', '\e' and '\v' in strings.