Directives and commands

A directive starts with # and controls the flow of the worksheet. A command starts with $ and takes arguments in braces. In a sheet, both are written on >> lines (or inside a calcpad fence), except the ones the sheet has its own form for (if, for, while, repeat, plot).

Conditions

M = 150kN*m
#if M < 100kN*m
    'OK
#else if M < 200kN*m
    'Check again
#else
    'Too large
#end if

The condition can be any expression that gives a number: zero is false. A condition that cannot be evaluated (an undefined name, say) is an error, and the block is left unresolved: no branch runs. CalcpadCE would silently take the #else branch; see Deviations from CalcpadCE.

Loops

#repeat 3
    y = 2
#loop

#for i = 1 : 4
    #if i ≡ 3
        #continue
    #end if
    s = i
#loop

s = i = 1
s = i = 2
s = i = 4

Pass 3 is skipped by #continue.

n = 0
#while n < 3
    n = n + 1
#loop

#break leaves the loop and #continue skips to the next pass. Every line in the loop prints on every pass, so use #hide around the body when you only want the final value. The commands $Sum, $Product, $Repeat and $While do the same without printing each pass.

Macros and string variables

Macros are text substituted before the worksheet is calculated. A name ends with $.

#def twice$(a$) = 2*a$
r = twice$(7)

r = 2·7 = 14

A multi-line macro repeats a whole block with different values:

#def beam$(span$; load$)
    M = load$*span$^2/8
    V = load$*span$/2
#end def
beam$(6m; 12kN/m)

M = 12 kN/m · (6 m)² / 8 = 9 kN·m
V = 12 kN/m · 6 m / 2 = 36 kN

The macro text does not have to be valid Calcpad by itself. It is substituted first and parsed after. Unwrapped in the results views shows the text after substitution, which is the place to look when a macro misbehaves. A macro cannot contain another definition; it can use an earlier one.

Modules

#include name.cpd pulls in a file from the library (see Saving). Put shared definitions in a file with a #global section and keep the worksheet-specific part in #local: only the global part is included when the file is imported.

Constants

#const g_n = 9.81m/s^2
F = 70kg*g_n|N

A #const cannot be changed later.

Number format

#round n rounds output to n digits, #round default goes back; #format spec sets a custom format string (for example #format 0.00). The Decimals setting sets the default. #settings {"decimals": 4} overrides engine settings for the lines that follow.

Text modes

#md on and #md off turn Markdown on and off in comment lines. #markdown … #end markdown and #html … #end html switch to a block of Markdown or raw HTML, and #cpd goes back to calculation inside one.

#markdown
## Section

* one
* two
#end markdown

Reading and writing data

#read M from file.csv, #write M to file.csv and #append M to file.csv move a matrix between the worksheet and a text, CSV or Excel file in the library. Options choose the cell range (@R1C1:R2C2 for text, @Sheet1!A1:B2 for Excel), the matrix type and the separator. The full forms are in the reference.

A worksheet that writes files saves them into the library and downloads them when their content changes.

Numerical commands

#rad
f(x) = x^3 - 2*x - 5
r = $Root{f(x) @ x = 2 : 3}
A = $Area{sin(x) @ x = 0 : π}
m = $Slope{x^3 @ x = 2}
hi = $Sup{sin(x) @ x = 0 : 3}
S = $Sum{1/k^2 @ k = 1 : 100}
P = $Product{k @ k = 1 : 5}

r = $Root{f(x) = 0; x ∈ [2; 3]} = 2.09
A = ∫ sin(x) dx from 0 to π = 2
m = d/dx x³ at x = 2 = 12
hi = $Sup{sin(x); x ∈ [0; 3]} = 1
S = Σ 1/k² for k = 1 to 100 = 1.63
P = Π k for k = 1 to 5 = 120

Command	Meaning
`$Root{f(x) @ x = a : b}`	A root of f in the interval. `$Root{f(x) = c @ ...}` solves f(x) = c.
`$Find{f(x) @ x = a : b}`	An approximate solution, when the exact value is not needed.
`$Sup`, `$Inf`	Local maximum or minimum.
`$Area`	Numerical integral (adaptive Gauss-Lobatto).
`$Integral`	Numerical integral (tanh-sinh).
`$Slope{f(x) @ x = a}`	Derivative at a point.
`$Sum`, `$Product`	Iterative sum and product.
`$Repeat`, `$While`, `$Block`, `$Inline`	Iterative expression blocks.
`$Plot`, `$Map`	Plots; see Plots.

The relative precision of the numerical methods is the Precision setting (default 1e-12).