Thinking Domain Math

Thinking domain math is a simple freeform spreadsheet style.

Cells are in the form: HOW_TO_FORMAT VARIABLE_NAME (VALUE) OPERATOR

HOW_TO_FORMAT

• $ dollars with optional cents
• % percent format
• ? generic decimal format

VARIABLE_NAME

• any combination of lower case letters or an underscore

(VALUE)

• A numeric value or a mathjs expression

OPERATOR

• How to apply this number to the variable RPN style. One of + – * / =

So lets say you want to add up a tool list. In your editor you would have these cells

• Portable drill \$tool(89.95)+
• Hammer \$tool(15.20)+
• Saw \$tool(22.50)+
• Chisel \$tool(3)+
• Total \$tool()

And in your thought or comment you would see

• Portable drill $tool(89.95)+
• Hammer $tool(15.20)+
• Saw $tool(22.50)+
• Chisel $tool(3)+
• Total $tool()

The default operator is = which assigns the output of the cell to the respective variable.

The default variable name is tot so if you are only adding up one set of things per thought you can leave off the variable name and simply put \$(89.95) and \$(15.20) etc. and the total can simply be either \$() or \$tot() as you like. You can also use the default variable as a junk or scratchpad variable to display expressions when you don’t need the result placed in a named variable, for example \?(a * b + c) which will display the expression result and incidentally add the result to tot which can be ignored.

Display-only cells (those without expressions or values) are expanded on a second pass so they always show final results for that variable. This allows display cells like \$tool() to be anywhere, even at the top, and still show totals. If you want to show the current value of a variable, basically the subtotal, at that place in the page, you can put the word now in the cell like this \$tool(now).

Math cells can go anywhere. Inside table cells, in free text, wherever you want.

Some examples of JavaScript math expressions that can be in cells

\$a(22.50) → $a(22.50)
\$b(abs(-22)) → $b(abs(-22))
\?c(pow(2,3)) → ?c(pow(2,3))
\?d(2 ^ 3 + 5 / 13) → ?d(2 ^ 3 + 5 / 13)
\?e(pow(2,3) + (5 * 2)) → ?e(pow(2,3) + (5 * 2))

\$f(a + 0.50) → $f(a + 0.50) ← yes, variables are expanded
\$f(20)- → $f(20)-
\$f() → $f()

\?(pi) → ?(pi)

Additional operators for sums and totals

The ~ and () operators allow changing the context for variable expansion. This is mainly useful for summing rows and displaying complex totals. These operators are mainly for generating display, though the ~ operator does assign the displayed (subtotal) value into the respective variable which is nice for gaining access to those values.

The ~ operator works like the = operator in that it fills the designated variable except that it causes variables being expanded to take on the value that was last operated on (i.e. visble) for that variable instead of the current value of the variable in the sheet. You can think of this like a row sum … though it is not limited to a physical row or to only summing, as the expression can be any valid mathjs expression.

Example: \$(a+b)~ will show the last value used to change variable a added to the last value used to change variable b … which if in the same row, would be the sum of the values those cells are showing in the current row.

The () operator defers this cell to the second pass, hence all variables in any expression have their final value no matter where they are in the flow of the page.

Example: \$(a-b+c)() would show the result of the expression a – b + c after all other operations on a and b and c are complete, no matter where in the page this cell is physically located.

For example, here is a nice little spreadsheet utilizing math cells with these operators.
 

item	cost	paid	remaining
Skirting	\$k(250)+	\$p(250)+	\$(k-p)~
6 Blocks	\$k(1.50*6)+	\$p(0)+	\$(k-p)~
Jack	\$k(30)+	\$p(0)+	\$(k-p)~
Total	\$k()	\$p()	\$(k-p)()

and the output is
 

item	cost	paid	remaining
Skirting	$k(250)+	$p(250)+	$(k-p)~
6 Blocks	$k(1.50*6)+	$p(0)+	$(k-p)~
Jack	$k(30)+	$p(0)+	$(k-p)~
Total	$k()	$p()	$(k-p)()

And hey, if you just want to calculate something simple, like the ounces in coke can, you can simply put it in the page as mathjs. The formula is PI * radius^2 * height / oz conversion

ounces in a coke can = \?(
radius = 1.25;
height = 4.415;
conversion = 1.805;

pi * radius ^ 2 * height / conversion;
)

ounces in a coke can = ?(
radius = 1.25;
height = 4.415;
conversion = 1.805;

pi * radius ^ 2 * height / conversion;
)
 

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