Syntax Differences

Function Limit per Program File
Only one function per program file
Other programs can be called as many as you want

Preprocessors Directives
#define K_ESC    27               //  Only #define constant

Local Variables
//  Each variable name must be unique and not a subset of other
// zThisIs and zThis are not supported, Vouch parser is a confused parser
//  Declaration in one line separated by commas
local zAbc, z123 
//  Initialization in another lines                    
zAbc := 123
z123  := afill( array( 10 ), 0 )   
// While initializing use different line for each variable, though comma separated syntax is supported 
zAbc := 0, z123 := array( 10 )
// Clipper/xBase++ uses semicolon for single line multiple assignments. Vouch uses  commas.

Static and Public Variables
Declaration of these variable types is not allowed. However Vouch provides a set of pre-defined public variables which are not used by Vouch itself.  There are 40 variables in this category,
pz1, pz2, pz3, ... , pz10
wz1,                       wz10
xz1,                         xz10
yz1,                         yz10
which can freely be used in Vouch programs. Please note that these variables are not thread safe (xBase++).

Loops
// It is perfectly right in Clipper/xBase++
local lMore, zNum
lMore := .t.
zNum := 212
do while .t.
   if zNum > 313
      exit
   endif
   nNum := nNum + 1
enddo

// In Vouch you must return at the begining of loop to terminate, exit clause is not
// supported. 
lMore := .t.
do while lMore
   if nNum > 313
      lMore := .f.
   endif
   nNum := nNum + 1
enddo

Operator Usage
// nNum++ is correct in Clipper/xBase++, but in Vouch this notation is valid
nNum := nNum + 1    

Code Blocks
Code blocks are supported. But there is a limitation, that is, only one code block per line of program. 

eval( {|| zVrb := zVrb + 1 } ) .and. eval( { || z2nd := xSomething } ) // Wrong
if eval( {|| zVrb := zVrb + 1 } ) > 3000 .and. zPkz  < 4000    // Right
   do something
endif