- Literal
- A literal is a constant value that can be either a number, a character,
or a string.
Number | CharLiteral | TextLiteral
- Identifier
- Identifiers are names given to types, procedures, constants, etc. They
consist of a letter followed by one or more letters, digits, and
underscores. Modula-3 is case sensitive, so identifiers with the same
letters in different cases are different identifiers. Example: test,
a_5
Letter { Letter | Digit | "_" ... }
- CharLiteral
- A character literal represents a single ASCII character (type CHAR).
Example: 'A', '\n', '\015'
"'" (PrintingChar | Escape | ") "'"
A PrintingChar is a letter, digit, punctuation mark, or any
ISO-Latin-1 code in [ 160..255 ]. An Escape is one of the
following:
- "\n": a newline character
- "\t": a tab character
- "\r": a carriage return character
- "\f": a formfeed character
- "\\": a \ character
- "\"": a " character
- "\'": a ' character
- "\" OctalDigit OctalDigit OctalDigit: a specific CHAR value, where OctalDigit is a digit in the range [0..7]. Example: \015 (char 13)
- TextLiteral
- A text literal represents a value of type TEXT (a string). Example:
"Hello.\n"
" { PrintingChar | Escape | "'" ... } "
PrintingChar and Escape have the same meanings as given above.
- Number
- A number is an integer or floating point number. Integers can be
expressed in any base [2..16] by writing the base followed by "_" and
the number in that base. Example:
2_1010 (base 2) =
8_12 (base 8) = 10 (base 10) = 16_A (base 16).
Floating point numbers can be expressed in the conventional scientific
notation as follows:
Digit { Digit ... } "." Digit { Digit ... } [ Exponent ]
where
Exponent = "E" | "D" | "X" [ "+" | "-" ] Digit { Digit ... }