Matrix Elements VB-800 Instrukcja Użytkownika Pobierz pdf (Strona 155)

A6.8 Expressions 147

extra column (~ )orrow(|) is pre/appended. If both operands are a matrix, the matrices

are joined. Note that the dimensions need not match: missing elements are set to zero

(however, a warning is printed of non-matching matrices are concatenated). Horizontal

concatenation has higher precedence than vertical concatenation.

Two strings or an integer and a string can be concatenated, resulting in a longer

string. Both horizontal and vertical concatenation yield the same result.

The result is most easily demonstrated by examples:

print(1 ~ 2 ~ 3 | 4 ~ 5 ~ 6); // <1,2,3; 4,5,6>

print("tinker" ~ ’&’ ~ "tailor" ); // "tinker&tailor"

print(<1,0; 0,1> ~ 2); // <1,0,2; 0,1,2>

print(2 | <1,0; 0,1>); // <2,2; 1,0; 0,1>

print(<2> ~ <1,0; 0,1>); // <2,1,0; 0,0,1>

When the operands are an address of a function, the result is an array of functions,

see §A6.6.3.

A6.8.9 Dot-relational expressions

The dot relational operators are .<, .<=, .>, .>=, .==, ./=, standing for ‘dot less’, ‘dot

less or equal’, ‘dot greater’, ‘dot greater or equal’, ‘is dot equal to’, ‘is dot not equal to’.

They conform to Table A6.3, except when both arguments are a string, in which

case the result is as for the non-dotted versions.

If both arguments are scalar, the result type inherits the higher type, so 1>=1.5

yields a double with value 0.0. If both operands are a matrix the return value is a matrix

with a 1 in each position where the relation is true and zero where it is false. If one of

the operands is of scalar-type, and the other of matrix-type, each element in the matrix

is compared to the scalar returning a matrix with 1 at each position where the relation

holds.

String-type operands can be compared in a similar way. If both operands are a

string, the results is int with value 1 or 0, depending on the case sensitive string com-

parison.

In if statements, it is possible to use matrix values. Remember that a matrix is true if

all elements are true (i.e. no element is zero).

A6.8.9.1 Logical dot-NOT expressions

The operand of the logical .not operator must have arithmetic type, and the result is 1

if the operand is equal to 0 and 0 otherwise. For a matrix, logical negation is applied to

each element.

A6.8.10 Logical dot-AND expressions

The dot-or operator is written as .\&\& or .and. It returns 1 if both of its operands

compare unequal to 0, 0 otherwise. Both operands must have arithmetic type. Handling

of matrix-type is as for dot-relational operators: if one or both operands is a matrix,

the result is a matrix of zeros and ones. Unlike the non-dotted version, both operands

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Matrix Elements VB-800 Instrukcja Użytkownika Strona 155