Visual Prolog 7.5 New Features


A major new feature of Visual Prolog 7.5 is the support for creating Web Services/Applications. See the Web Services tutorial for details.

Build 7500


  • Improved procedure check for number ranges (e.g. [1..3])
  • if-then-else expression (in addition to the existing if-then-else statement)
  • The condition in an if-then-else now contains an implicit cut, and thus allows non-deterministic condition
  • Improved garbage collection: Typed allocation of objects reduces the possibility of false pointers
  • Language C/C++ virtual object call compatibility (language thiscall)
  • New attribute [inline(size)] for inlining byte sequences in structs
  • Additional string literals syntax
  • Operator in for member test and iteration
  • New hasDomain/2-> function, in addition to the existing hasDomain/1 predicate
  • New deterministic orelse operator
  • Warning for superfluous static initialization of an object fact if this fact is also initialized in all constructors (the corresponding warning is switched off by the default)
  • Warning for unused local domains, functors and constants


  • New packages scannerSupport and cursorScannerSupport for writing scanners in Visual Prolog
  • New package service for creating services in Visual Prolog
  • New package parser for LALR(1) parsing
  • stream::allowNullPointers property for robust writing of illformed data that contains null-pointers
  • readLineCRLF/0-> predicate that copy <CR><LF> to resulting string.
  • New packages for standalone HTTP/HTTPS server (httpRequest, ...)
  • New package json for JSON representation, parsing and writing
  • New packages for JSON-RPC service support: standalone HTTP/HTTPS and/or ISAPI integration into Microsoft Internet Informantion Services, IIS (jsonRpc, jsonRpcService, ...)
  • New package watchDirectory (pfc\communications) for monitoring directory changes
  • New package sciLexerStatusBar for editor status line
  • New packages for XML parsing/writing according to XSD definition (xmlSupport, fromXmlDomSupport and toXmlDomSupport)
  • GDI+ support for multi image icons in the icon class (utilized by the ribbonControl).


Vip is a directory (Commercial Edition only) that provides access to certain internal tools and structures, here among:

  • The Visual Prolog parser
  • Project file api
  • New package for LALR(1) parser generator


  • MDI template: new status bar replaces old vpi toolbar
  • SDI template: uses ribbon and new status bar
  • "Find usages" tool, for finding usages og predicates/properties/facts in clauses
  • Copy a project in Welcome/Open Project window
  • Error message corrector for missing/invalid scope
  • Project file in XML (*.vipprj)
  • Project Tree: directories preview
  • Refactoring
    • move folder or package
    • Set namespaces on a complete package (recursively)
  • The possibility for adding a resorce entity (dlg, or class, etc.) without creating a package


  • Collections (map, set) displayed more user friendly in variables/etc window


  • Tool for generating XML parser/writer from XSD files
  • PIE: Support for integer64

Build 7501

Build 7501 mainly contains bug fixes as listed below. But the commercial edition also contains an LALR Parser Generator.


  • Problem with Must-Unify
  • Problem with predicate constants
  • Error using properties from a generic interface
  • Numeric conversion error in machine instructions generation
  • Error on retractAll because of invalid code generation (registers management)
  • Must-unify leads to access violation when raising proper runtime error (type library passed to runtime function does not correspond to a term)
  • Dump in static facts initialization
  • Wrong unused domain warning
  • Problems with option: /READOnlyterm
  • Incorrect list element allocation if it has type like A*
  • Exception in 64 bit program (large local static size problem)
  • Invalid debug information for type libraries
  • Recycling bug for open-statements which can be resolved both to a class declaration and interface definition
  • Access violation in example (incorrect type library for allocation)
  • Illegal error for free type parameter in type expression



  • IDE API setCurrentDirectory fails
  • Exception 'Single fact 'oleInPlaceObject_fact' from internal database 'activeXcontrol::activeXcontrol@objectDB' has no value'
  • Wrong F12 on _builtIn::compare
  • Exception 'No active window' in menuhandle::updateRefactorItems/1
  • Project Settings\Version: Change description does not trigger new resource compilation
  • Exception 'emptyString' during browse search for xxx::
  • Changing an IDE variable without opened project gives an exception
  • Too long effect of "Apply this action to subsequent files" flag
  • Tooltip should use proper brackets for generic argument: {@T} instead of (@T)
  • Ctrl+S does not save edited not-project file
  • Menu preview improvements
  • IDE doesn't remove resources from project
  • IDE doesn't create .bro file with new console without manifest
  • timerControl exception in IDE


  • xmlSerializerGenerator: generation of types with incorrect dashes
  • ChainDB 64bit: Memory overriding (not-aligned arrays of internal structures that contain pointers)
  • Solution manager: clicking vipsln files opens the solution manager, but the solution is not loaded

Build 7502

Build 7502 contains bug fixes as listed below.



  • Wrong handling of NULL fields in 64 bit ODBC (gives "string right truncation" error).


  • PIE exception in IDE when debugging 64 bit programs

See also