This returns the upper limit of the array for the dimension requested.
The dimension defaults to one if not specified. Specifying a dimension
value of 0 will return the current value of OPTION BASE.
Unused dimensions will return a value of zero.
For example:
DIM myarray(44,45)
BOUND(myarray(),2) will return 45

/* all memory allocation (except for the heap) is made by m_alloc()
  memory layout used by MMBasic:

         |--------------------|    <<<   This is the end of the RAM allocated to MMBasic (defined as RAMEND)
         |                    |
         |    MMBasic Heap    |
         |    (grows down)    |
         |                    |
         |--------------------|   <<<   VarTableTop
         |   Variable Table   |
         |     (grows up)     |
         |--------------------|   <<<   vartbl
                                        This is the start of the RAM allocated to MMBasic (defined as RAMBASE)

  m_alloc(type, size) is called when the program is running and whenever the variable table needs to be expanded

  Separately calls are made to GetMemory() and FreeMemory() to allocate or free space on the heap (which grows downward
  towards the variable table).  While the program is running an out of memory situation will occur when the space between
  the heap (growing downwards) and the variable table (growing up) reaches zero.

b=Asc("T")
a$="cat in hat"
Print a$, Peek(var a$,3)
Poke var a$,3,b
Print a$, Peek(var a$,3)
End

cat in hat       116
caT in hat       84
>

i=0:z=1
Do

  j=Peek(progmem, i)
  If j>127 Then
    Print "[" Str$(J) "]";
  Else If j<32 Then
    Print "<" Str$(J) ">";
  Else
    Print Chr$(j);
  EndIf

  If j=0 Then Print :If z=0 Then End
  i=i+1:z=j

Loop

Saved 163 bytes
<1>[159]i[198]0<0>
[159]z[198]1<0>
<1>[132]<0>
<1><0>
<1>  [159]j[198][208]progmem, i)<0>
<1>  [156]j[197]127 [177]<0>
<1>    [166]"[" [164]J) "]";<0>
<1>  [134]j[196]32 [177]<0>
<1>    [166]"<" [164]J) ">";<0>
<1>  [136]<0>
<1>    [166][134]j);<0>
<1>  [142]<0>
<1><0>
<1>  [156]j[198]0 [177] [166]<0>
[156]z[198]0 [177] [144]<0>
<1>  [159]i[198]i[186]1<0>
[159]z[198]j<0>
<1><0>
<1>[162]<0>
<0>
>

here: Rem this is a label
61680 Rem this is a line number

<1><0>
<1><3><4>here [169]this is a label<0>
<1><2>[240][240] [169]this is a line number<0>
<0>