AsciiMath support
Metanorma uses the Ruby AsciiMath parser to process AsciiMath, converting it to MathML for Metanorma processing. For rendering in HTML, the MathML generated is processed by MathJax. For rendering in Word, the MathML is converted to Office Open XML (OOXML).
Note

AsciiMath only recognises decimal points and not decimal commas. Any attempt to use a decimal comma (e.g. 3,4) will be processed as an operator, and will end up treating the integer and fractional parts of the number as two separate numerals, separated by a space as well as a comma. This applies to all versions of Asciimath. 
Ruby AsciiMath
The version of AsciiMath supported by the Ruby AsciiMath parser is slightly different to other variants of AsciiMath. The following are differences between Ruby AsciiMath and the version of AsciiMath documented on asciimath.org:
Miscellaneous symbols:
Ruby AsciiMath adds the following as distinct symbols:
dx

dx identifier
dy

dy identifier
dz

dz identifier
dt

dt identifier
…

… operator
"\ "

nonbreaking space
qquad

four nonbreaking spaces (just as
quad
is processed as two nonbreaking spaces) lim

lim operator
Lim

Lim operator
'

prime operator, ′
:'

∵
/_\

△
frown

⌢
Relation symbols
Ruby AsciiMath adds the following as distinct symbols:
:=

:= operator
Operation symbols
setminus

\
divide

÷
::

 as operator
Logical symbols
No difference.
Grouping brackets
Ruby AsciiMath adds the following as distinct brackets:
:

 as left bracket
:

 as right bracket
Arrows
No difference.
Accents
The following operators are currently missing from Ruby AsciiMath:

color(red)(x)

cancel(x)
Ruby AsciiMath adds the following as distinct accents
tilde

~
overarc

⏜
Greek letters
The Ruby AsciiMath gem supports several capital letter symbols, which are not named in asciimath.org:
Alpha

Alpha
Beta

Beta
Epsilon

Epsilon
Zeta

Zeta
Eta

Eta
Iota

Iota
Kappa

Kappa
Mu

Mu
Nu

Nu
Rho

Rho
Tau

Tau
Upsilon

Upsilon
Chi

Chi
Standard functions
No difference.
Font commands
The following are font commands supported by the Ruby AsciiMath gem, in addition to those named in asciimath.org:
ii

italic font
bii

bold italic font
bcc

bold script font
bfr

bold fraktur font
bsf

bold sans serif font
sfi

italic sans serif font
sfbi

sans serif bold italic font
Conversion to Word OOXML
AsciiMath and MathJax processors are tolerant of loose syntax in mathematical expressions.
Currently the conversion of MathML to OOXML is not as tolerant: if a mathematical operator
takes a single argument, the OOXML expects to find that argument brackets as a single entity.
If that does not happen, Word displays a dotted square where it would expect the single
argument to appear. To remedy this, you will need to bracket the argument of the operator
in invisible brackets ({:
, :}
).
For example, the following AsciiMath displays correctly in HTML under MathJax:
[stem]
++++
bar X' = (1)/(v) sum_(i = 1)^v t_i
++++
However, it displays incorrectly in Word with an extraneous “square”:
That is because the sum
operator expects to find a single expression as its argument,
but t_i
is processed as two tokens. To get this expression processed correctly for
Word, you will need to bracket t_i
:
[stem]
++++
bar X' = (1)/(v) sum_(i = 1)^v {:t_i:}
++++
and it should display correctly as: