Variable naming syntax

CalcTree variables use custom syntax that let you create variables that work as functional calculations (in 'code-friendly' form) while displaying also rendering as clean mathematical notation. This system uses underscores and special keywords to control subscripts, superscripts, mathematical symbols, and other formatting.

Basic Concepts

Simple Names

• Regular variable names display as-is:

  • velocity → $velocity$

  • force → $force$

  • temperature → $temperature$

• Names ending with underscore use regular font with spaces:

  • total_cost_ → $total \space cost$

  • heat_flow_rate_ → $heat \space flow \space rate$

  • max_speed_ → $max \space speed$

  • Note: The trailing underscore converts underscores to spaces

Special Separators

Single Underscore _ Rules

A single underscore has different meanings depending on what follows it:

For regular text - creates subscripts:

• v_max → $v_{max}$

• F_applied → $F_{applied}$

• x_1 → $x_1$

For Greek keywords - converts and subscripts:

• alpha_1 → $\alpha_1$ (converts 'alpha' to α and subscripts '1')

• sigma_yield → $\sigma_{yield}$(converts 'sigma' to σ and subscripts 'yield')

For special keywords - triggers special formatting:

• x_prm → $x'$ (prime right notation)

• prm_x → $'x$ (prime left notation)

• ovr_x → $x̄$ (overline for averages)

Combined with double underscore for superscripts:

• x_1__2 → x₁² (x subscript 1, squared)

• v_final__2 → v_final² (final velocity squared)

Formatting Syntax

Subscripts and Superscripts

Use underscores followed by special placeholders:

Syntax	Result	Example
name_text	Subscript	v_max → $v_{max}$
name__text	Superscript	x__2 → $x^2$
name_sub__sup	Both	x_i__2 → $x_i^2$

Complete Mathematical Symbol Reference

CalcTree automatically converts certain keywords to mathematical symbols when a variable is rendered on the page:

Lowercase Greek

Keyword	Symbol	Example	Display
alpha	α	alpha_1	$\alpha_{1}$
beta	β	beta_coefficient	$\beta_{coefficient}$
gamma	γ	gamma_ray	$\gamma_{ray}$
delta	δ	delta_t	$\delta_{t}$
epsilon	ε	epsilon_0	$\epsilon_{0}$
zeta	ζ	zeta_function	$\zeta_{function}$
eta	η	eta_efficiency	$\eta_{efficiency}$
theta	θ	theta_angle	$\theta_{angle}$
iota	ι	iota_value	$\iota_{value}$
kappa	κ	kappa_constant	$\kappa_{constant}$
lambda	λ	lambda_wavelength	$\lambda_{wavelength}$
mu	μ	mu_friction	$\mu_{friction}$
nu	ν	nu_frequency	$\nu_{frequency}$
xi	ξ	xi_parameter	$\xi_{parameter}$
omicron	ο	omicron_value	$\omicron_{value}$
pi	π	pi_constant	$\pi_{constant}$
rho	ρ	rho_density	$\rho_{density}$
sigma	σ	sigma_stress	$\sigma_{stress}$
tau	τ	tau_torque	$\tau_{torque}$
upsilon	υ	upsilon_velocity	$\upsilon_{velocity}$
phi	φ	phi_angle	$\phi_{angle}$
chi	χ	chi_squared	$\chi_{squared}$
psi	ψ	psi_wave	$\psi_{wave}$
omega	ω	omega_angular	$\omega_{angular}$

Uppercase Greek

Keyword	Symbol	Example	Display
Alpha	Α	Alpha_particle	$\Alpha_{particle}$
Beta	Β	Beta_function	$\Beta_{function}$
Gamma	Γ	Gamma_distribution	$\Gamma_{distribution}$
Delta	Δ	Delta_H	$\Delta_{H}$
Epsilon	Ε	Epsilon_field	$\Epsilon_{field}$
Zeta	Ζ	Zeta_potential	$\Zeta_{potential}$
Eta	Η	Eta_meson	$\Eta_{meson}$
Theta	Θ	Theta_temperature	$\Theta_{temperature}$
Iota	Ι	Iota_index	$\Iota_{index}$
Kappa	Κ	Kappa_number	$\Kappa_{number}$
Lambda	Λ	Lambda_baryon	$\Lambda_{baryon}$
Mu	Μ	Mu_mass	$\Mu_{mass}$
Nu	Ν	Nu_neutrino	$\Nu_{neutrino}$
Xi	Ξ	Xi_cascade	$\Xi_{cascade}$
Omicron	Ο	Omicron_variant	$\Omicron_{variant}$
Pi	Π	Pi_product	$\Pi_{product}$
Rho	Ρ	Rho_meson	$\Rho_{meson}$
Sigma	Σ	Sigma_sum	$\Sigma_{sum}$
Tau	Τ	Tau_lepton	$\Tau_{lepton}$
Upsilon	Υ	Upsilon_meson	$\Upsilon_{meson}$
Phi	Φ	Phi_flux	$\Phi_{flux}$
Chi	Χ	Chi_distribution	$\Chi_{distribution}$
Psi	Ψ	Psi_function	$\Psi_{function}$
Omega	Ω	Omega_resistance	$\Omega_{resistance}$

Greek Variations

Keyword	Symbol	Description
varepsilon	$\varepsilon$	Variant epsilon
varkappa	$\varkappa$	Variant kappa
varphi	$\varphi$	Variant phi
varpi	$\varpi$	Variant pi
varrho	$\varrho$	Variant rho
varsigma	$\varsigma$	Variant sigma
vartheta	$\vartheta$	Variant theta

Special Mathematical Symbols

Keyword	Symbol	Example	Display
infty	∞	T_infty	$T_{\infty}$
diameter	⌀	d_diameter	$d_{\varnothing}$
circ	°	angle_circ	$angle_{\circ}$
mid	|	x_mid	$x_{\mid}$
degree	°	temp_degree	$temp_{\degree}$
star	⋆	rating_star	$rating_{\star}$

Punctuation & Operators

These symbols are inserted in the baseline (not as subscripts) when preceded by a single underscore:

Keyword	Symbol	Example	Display
prm	'	x_prm	$x'$
dot	.	v_dot	$\dot{v}$
cma	,	item_cma_1	$item, 1$
div	/	m_div_s	$m/s$
spc	(space)	total_spc_cost	$total \; cost$
num	#	item_num_5	$item\#5$
pls	+	charge_pls	$charge+$
mns	-	ion_mns	$ion-$

Special Directives

These create formatting effects:

Keyword	Effect	Example	Display
sqrt	Square root	value_sqrt	$\sqrt{value}$
prn	Parentheses	sum_prn	$(sum)$
ovr	Overline	x_ovr	$\overline{x}$

Advanced Formatting

Special placeholder keywords after underscores:

Examples

Engineering Variables

Stress components:

• sigma_xx → $\sigma_{xx}$ (sigma with xx subscript)

• sigma_y__2 → $\sigma_{y}^{2}$ (sigma with y subscript and squared)

• tau_xy → $\tau_{xy}$ (shear stress)

Heat transfer:

• q_dot_ → $q \; dot$ (heat flux, regular font)

• T_infty → $T_{\infty}$ (temperature at infinity)

• alpha_thermal → $\alpha_{thermal}$ (thermal diffusivity)

Electrical:

• V_rms → $V_{rms}$ (RMS voltage)

• I_peak__2 → $I^{2}_{peak}$ (peak current squared)

• Omega_resistance → $\Omega_{resistance}$ (resistance in ohms)

Physics & Mathematics

Wave functions:

• psi_n → $\psi_{n}$ (wave function n)

• Psi_total → $\Psi_{total}$ (total wave function)

Statistics:

• mu_population → $\mu_{population}$ (population mean)

• sigma_x → $\sigma_{x}$ (standard deviation)

• chi__2 → $\chi^{2}$ (chi-squared)

Calculus:

• Delta_x → $\Delta_{x}$ (change in x)

• epsilon_0 → $\epsilon_{0}$ (permittivity of free space)

Reserved Keywords

These words cannot be used as variable names:

MathJS Reserved: mod, to, in, and, xor, or, not, end

Python Reserved (for compatibility): False, None, True, and, as, assert, async, await, break, class, continue, def, del, elif, else, except, finally, for, from, global, if, import, in, is, lambda, nonlocal, not, or, pass, raise, return, try, while, with, yield

Best Practices

1. Use meaningful base names: sigma_yield is better than just sigma

2. Be consistent: Use the same naming patterns throughout your project

3. Consider context: Delta_T for temperature change, delta_small for small changes

4. Mix symbols wisely: alpha_beta_ratio → $\alpha_{beta\_ratio}$ (only first part converts)

Quick Reference Card

• Basic subscript: variable_subscript → $variable_{subscript}$

• Basic superscript: variable__superscript → $variable^{superscript}$

• Both: variable_sub__sup → $variable_{sub}^{sup}$

• Greek letter: alpha_1 → $\alpha_{1}$

• Uppercase Greek: Delta_x → $\Delta_{x}$

• Regular font (spaces): my_variable_ → $my \; variable$

• Overline: x_ovr → $\overline{x}$

• Square root: value_sqrt → $\sqrt{value}$

• Parentheses: term_prn → $(term)$

• Prime notation: x_prm → $x'$

• Infinity: T_infty → $T_{\infty}$

• Multi-part: part1_bsl_part2 → $part1/part2$

Troubleshooting

Variable not displaying as expected?

• Check if you're using the correct number of underscores

• Verify the keyword is in the supported symbols list

• Ensure no typos in placeholder keywords

Calculation errors?

• Confirm the base name is a valid identifier

• Check for reserved keywords conflict

• Verify syntax without special formatting first