GUI – String handling

General issue

When reading in a text string, the executable detects each \ and " and waits for the following character before deciding what to do. The handling is shown in the following table:

From	To
\\	\
\"	"
""	"

You might be used to Microsoft Visual Basic or Microsoft VBA which (I think) has a richer set of conversions, and (I think) requires that a single \ is always input as \\

This executable will treat the follow string definitions as generating the same result:

dir("z:\some path")
dir("z:\\some path")

Rather than have the richness found in some other languages, this executable lets you insert unusual characters by using the chr ( value ) command

So to insert a tab you could use

dim myString ="Hello" & chr(0x09) & "world"
message = myString

 

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Text string commands

work in progress!

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FreeString

An internal variable used to hold a user defined string.

The power of this variable is that it is internally linked to some special handling.
Specifically:
If an input line begins with > <string expression>
then the resulting action is FreeString = <string expression>

If an input line begins with >> <string expression>
then the resulting action is FreeString = freestring & <string expression>

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InStr

Checks to see if a string contains a specific sub-string. Optionally you can control whether the check is case sensitive or not. Default is case insensitive.

function InStr ( <“Look in” string expression> , <“Look for” string expression> , OPTIONAL <Case flag> )
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SubStr

Returns a substr from a source string.
Is syntactically the same as the SQLite command substr
and performs the same function as  this executable’s mid command.

function SubStr ( <Source string expression> , start at offset , OPTIONAL keep character count )
 
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InStrRex

Checks to see if a string contains a specific sub-string. Optionally you can control whether the check is case sensitive. Default is case insensitive.
Unlike the command instr the command InstrRex uses a regular expression as its second parameter

Returns 0 if no match, else returns the 1-based index of the start of the match

• The underlying regexp machine is based on the pcre2 “C” source files from https://www.pcre.org/
• Syntax: http://www.pcre.org/current/doc/html/pcre2syntax.html
  
  function  InstrRex ( <“Look in” string expression> , <“Regular Expression” string expression> )

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