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Modula-2 also makes available several built-in procedures and functions. In describing these, the following metavariables are used:

`a`

- represents an
`ARRAY`

variable. `c`

- represents a
`CHAR`

constant or variable. `i`

- represents a variable or constant of integral type.
`m`

- represents an identifier that belongs to a set. Generally used in the same function with the metavariable
`s`

. The type of`s`

should be`SET OF mtype`

(where`mtype`

is the type of`m`

). `n`

- represents a variable or constant of integral or floating-point type.
`r`

- represents a variable or constant of floating-point type.
`t`

- represents a type.
`v`

- represents a variable.
`x`

- represents a variable or constant of one of many types. See the explanation of the function for details.

All Modula-2 built-in procedures also return a result, described below.

`ABS(n)`

- Returns the absolute value of
`n`

. `CAP(c)`

- If
`c`

is a lower case letter, it returns its upper case equivalent, otherwise it returns its argument. `CHR(i)`

- Returns the character whose ordinal value is
`i`

. `DEC(v)`

- Decrements the value in the variable
`v`

by one. Returns the new value. `DEC(v,i)`

- Decrements the value in the variable
`v`

by`i`

. Returns the new value. `EXCL(m,s)`

- Removes the element
`m`

from the set`s`

. Returns the new set. `FLOAT(i)`

- Returns the floating point equivalent of the integer
`i`

. `HIGH(a)`

- Returns the index of the last member of
`a`

. `INC(v)`

- Increments the value in the variable
`v`

by one. Returns the new value. `INC(v,i)`

- Increments the value in the variable
`v`

by`i`

. Returns the new value. `INCL(m,s)`

- Adds the element
`m`

to the set`s`

if it is not already there. Returns the new set. `MAX(t)`

- Returns the maximum value of the type
`t`

. `MIN(t)`

- Returns the minimum value of the type
`t`

. `ODD(i)`

- Returns boolean TRUE if
`i`

is an odd number. `ORD(x)`

- Returns the ordinal value of its argument. For example, the ordinal value of a character is its ASCII value (on machines supporting the ASCII character set). The argument
`x`

must be of an ordered type, which include integral, character and enumerated types. `SIZE(x)`

- Returns the size of its argument. The argument
`x`

can be a variable or a type. `TRUNC(r)`

- Returns the integral part of
`r`

. `TSIZE(x)`

- Returns the size of its argument. The argument
`x`

can be a variable or a type. `VAL(t,i)`

- Returns the member of the type
`t`

whose ordinal value is`i`

.

Warning:Sets and their operations are not yet supported, soGDB treats the use of procedures

`INCL`

and`EXCL`

as an error.

Next: M2 Constants, Previous: M2 Operators, Up: Modula-2 [Contents][Index]