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textCallBack

handle text output in OpenMaple

 

Calling Sequence

Parameters

Description

Examples

Calling Sequence

textCallBack(data, tag, output)

Parameters

data

-

user_data pointer passed to StartMaple (Long)

tag

-

code indicating kind of text (Long)

output

-

output string (byte array pointer)

Description

• 

This OpenMaple function is part of the MapleCallBack structure passed as an argument to StartMaple.

• 

The textCallBack function is called with typical (non-exceptional) Maple output. The output that Maple generates, for example, an intermediate result or the output from a printf statement, is passed to the textCallBack function.

• 

The prototype for the function that you can assign to the entry in the MapleCallBack must resemble the following.

Sub TextCallBack(ByVal data As Long,

     ByVal tag As Integer,

     ByVal Output As Long)

• 

The tag parameter indicates the type of Maple output. The tag parameter can take one of the following values (as defined in maplec.h).

MAPLE_TEXT_OUTPUT

A line-printed (1-D) Maple expression or statement.

 

 

MAPLE_TEXT_DIAG

Diagnostic output (high printlevel or trace output).

 

 

MAPLE_TEXT_MISC

Miscellaneous output, for example, from the Maple

 

printf function.

 

 

MAPLE_TEXT_QUIT

Response to a Maple quit, done, or stop command.

 

 

MAPLE_TEXT_WARNING

A warning message generated during a computation.

 

 

MAPLE_TEXT_ERROR

An error message generated during parsing or

 

processing. This is generated only if you

 

do not specify an errorCallBack function.

 

 

MAPLE_TEXT_STATUS

Kernel resource usage status (a "bytes used"

 

message). This is generated only if you

 

do not specify a statusCallBack function.

 

 

MAPLE_TEXT_DEBUG

Output from the Maple debugger.

 

 

• 

The output parameter contains the output of the type indicated by the tag parameter. Each output string can be arbitrarily long.  Most output obeys interface(screenwidth), which is initially set to infinity.  Some output is not line-broken, including output generated by printf (which controls its own formatting).

• 

A single result may be split into multiple calls to the textCallBack function. In particular, this can happen when interfacescreenwidth is not infinity.  It is also true for formatted output like that generated by accessing help.  A single command can generate many calls with different output tags.

• 

The data parameter contains the same data as passed to StartMaple in the user_data parameter.

Examples

 Public Sub TextCallBack2(ByVal data As Long, ByVal tag As Integer, _

         ByVal Output As Long)

    Dim OutputString As String

    OutputString = MaplePointerToString(Output)

    If tag = MAPLE_TEXT_HELP Then

        Write #2, OutputString

    Else

        Write #1, OutputString

    End If

 End Sub

 ' assignment to MapleCallback entry

 cb.lpTextCallBack = GetProc(AddressOf TextCallBack)

 ' test statement that will invoke the TextCallBack

 EvalMapleStatement kv, "x^2+3*x+1;"

 EvalMapleStatement kv, "help(int);"

See Also

callBackCallBack

errorCallBack

interface

OpenMaple

OpenMaple/VB/API

OpenMaple/VB/Examples

queryInterrupt

readLineCallBack

redirectCallBack

StartMaple

statusCallBack

streamCallBack

 


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