On 21 June 2018 at 15:21, Dave Park via Ql-Users <ql-users@lists.q-v-d.com>
wrote:

> > SuperBASIC is quite unique in that it stores the *difference* in length
> of
> > a line compared to the previous line, along with its line number. This
> way,
> > because the current line length is also stored in a system variable, it
> can
> > search for lines in both backward and forward direction. So a proc/fn
> call
> > will be faster when the definition is closer to the calling line. This is
> > also mentioned in the Minerva documentation.
>
> ​Hmmm. Are they stored in a known order, eg: alphabetical or order of
> creation/declaration
>

They are stored in order of line number (it's Basic, after all...).


> > You cannot define a proc/fn multiple times but you can check the type and
> > usage of a parameter using the PARTYP, PARUSE, PARNAM$ and PARSTR$
> > functions in TK2 and act accordingly. An example of this is in my 'ls'
> > procedure which uses an extra parameter as a flag for recursive directory
> > searches. When this parameter is empty it only lists the current
> directory.
>
> ​I suppose it does reduce these stresses that while sBASIC has "strict"
> typing of variables, it allows easy transfer between variable types.​ It
> also has the concepts of undefined variables and defined but unset
> variables.
>

It's not as strict as it seems. What's also unique in S*BASIC is
'coercion'. You want to assign a numeric value to a string variable and
S*BASIC will happily do this, by converting the number to a string (in
other BASICs you would have to use STR$). And the other way round assign a
string value to a numeric variable (provided the string contains a valid
number).
The type of a parameter in a procedure or function is determined when the
function is *called*, not when it's defined. In a machinecode function you
can find out what type a parameter is and choose to evaluate it as a
number, string or name (in a BASIC function you can use the four TK2
functions mentioned above though you're probably a bit more restricted by
parameter types).
Also, variables are never undefined (they're defined as soon as you enter
their name in a program line) but they can be unset...


> Quite amazing for a language that fit in a very small part of 48K.


 And all written in 68K assembler in a few weeks time...

Jan.

-- 
*Jan Bredenbeek* | Hilversum, NL | j...@bredenbeek.net
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