Built-In Func/Proc (Debugging with GDB)

15.4.9.2 Built-in Functions and Procedures

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, so GDB treats the use of procedures INCL and EXCL as an error.