Cookbook

Complete recipes for things people ask handcalcs to do. Each one is a short, working example; most show the rendered output, produced when these docs were built. The GitHub issue that asked for it is linked where there is one.

Find a recipe

I want to…	Recipe
Numbers
set the precision of one variable	Precision of one variable
use scientific or engineering notation	Scientific notation, engineering notation
hide floating-point noise like 5.55e-17	Snap noise to zero
drop trailing zeros, add thousands separators	Trailing zeros, separators
Showing and hiding
show only the result of a line	Results only
show only formulas, or only results	Formulas or results for a section
hide a line, or the imports	Hide a line, hide imports
break a long equation	Long equations
render one line of a notebook cell	%render
lay out inputs in a grid	Inputs in a grid
Checks
mark a check with ✓ or ✗	Pass/fail marks
state pass or fail in words	Verdict in a comment
show only the governing case	Governing branch
check several load cases	Several cases at once
Notation
write Npl,Rd, ΔH, γM0	Subscripts, Greek letters
give a variable any symbol	Any symbol for any name
stop psi becoming ψ, or turn off subscripts	Keep a name as text, no subscripts
use Σ, ×, ∛, n! or my own function names	Functions, operators, cube roots and factorials
Units
calculate with forallpeople or pint	Units
show a result in particular units	Specific units
Reports
make a PDF, Word or HTML document	Write to a file, Word
number equations, add a title block	Equation numbers, title block
start a new page	Page breaks
change colors or alignment	Colors, alignment
Apps
render from a script, or a function	Scripts, functions
run one calculation for many designs	Many designs
show calculations in a web or desktop app	Web apps, desktop apps

How the recipes work

Most recipes need nothing but a comment command or a setting. The rest subclass a built-in renderer and change a class attribute or register a rule, the three levers described in Customizing a renderer. A recipe written for the Markdown renderer works on the LaTeX renderer too: register the same function on a LatexRenderer subclass.

To use a recipe’s renderer in Jupyter, import the module that defines it and select it by name, for example %hc_default_renderer eng_markdown.