Previous character in a group- Ch

- Instruction: Ch"%"

- Parameter: "%" one or more absolute characters or of type

- Return: true if the preceding character belongs to one of the characters in the specified group.

- Description:

Returns true if the preceding character belongs to one of the specified group characters. The characters in the group can be absolute or of type. An absolute character is the one that is immediately comparable, e.g. "abc123", i.e. all characters in the unicode set. Type characters are those belonging to a character type, such as letters, consonants, vowels, numbers, etc.. A type character is specified using the "\" activator followed by the character type. The list of type characters is as follows:

\* - Any character, except space

\w - Any letter or number

\? - Any letter

\# - Any number

\% - Any consonant

\& - Any vowel

\@ - Any accented vowel

\< - Any lowercase letter

\> - Any capital letter

\_ - Any punctuation

\' - Any apostrophe

\- - Any hyphen

\! - Any character other than letters, numbers and punctuation

\s - Any space

\n - Any null character (for example at the end or beginning of a line)

\\ - The inverted slash

The "Ch" instruction is a more immediate way than using multiple "Cp" and "Cl" instructions.

- Examples:

Text string: a

Braille string: 456

Condition: Ch "xy\#\@"

Description: Returns true if before the index the character is an "x", a "y", a number or an accented vowel. For example, "a" is transcribed with cell "456" if it is preceded by the character "x" (xa), by "y" (ya), by any number (5a" or by any accented vowel (ùa).

Text string: biblos

Braille string: 12 234

Condition: Ch"\_\s\n"

Description: Returns true if the word "biblos" is preceded by any punctuation mark, space or null character, so "biblos" is transcribed with cells "12 234".