# expr

## Description

Evaluate an expression using a C-like language. Variables and operators are used to create output values.

## Examples Combine many calculations into one object, even using functions not available in other objects

## Discussion

Use the expr object to perform mathematical calculations using C language-style mathematical operations. The object evaluates expressions that use the "variables" \$i1-\$i9 (the first to ninth inlets, taken as integers), \$f1-\$f9 (the inlets as floats) and \$s1-\$s9 (the inlets as symbols), and/or constants of the same types. The operators are +, -, *, /, &, |, &&, ||, !, ~, and ^, and you can also use a set of predefined mathematical and statistical functions. The list of functions in expr are as follows: min, max, int (convert to integer), float (convert to float), pow (power), sqrt (square root), exp (power of e to x), log10 (log), ln (natural log), log (nat. log), sin, cos, tan, asin (arcsin), acos, atan, atan2, sinh, cosh, tanh, fact (factorial), random, round, floor, ceil, size (size of a table), sum (sum of table contents), Sum (sum with boundaries), avg (of table contents), Avg (avg with boundaries), store (store into a table).

## Arguments

### expression [list]

The argument to the expr object is a mathematical expression composed of numbers, arithmetic operators such as + or *, comparisons such as < or >, C functions such as min () or pow (), names of table objects, and changeable arguments (\$i, \$f, and \$s) for ints, floats, and symbols received in the inlets.

### constant [number]

Numbers can be used as constants in the mathematical expression.

### inlet-format [symbol]

Changeable arguments that specify data formats associated with an inlet are described using a combination of a data type (\$i or \$f) and an inlet number (example: \$i2). The argument will be replaced by numbers received in the specified inlet.

### table-info [\$s]

Changeable arguments that specify accessing data from a table are described using the argument \$s and an inlet number which is replaced by the name of a table to be accessed. The argument should be immediately followed by a number in brackets specifying an address in the table. (Examples: \$s2 or \$s3[\$i1].)

### (other) [symbol]

The expr object understands the following arithmetic operators: +, -, *, /, %. Other operators are ~ (one's complement), ^ (bitwise exclusive or), &, &&, |, ||, and ! (not).

## Messages

### bang

In left inlet: Evaluates the expression using the values currently stored.

### int

#### Arguments

input [int]
The number received in each inlet will be stored in place of the \$i or \$f argument associated with it. (Example: The number in the second inlet from the left will be stored in place of the \$i2 and \$f2 arguments, wherever they appear.)

### (inlet1)

#### Arguments

input [int]
See the int listing.

### (inlet2)

#### Arguments

input [int]
See the int listing.

### (inlet3)

#### Arguments

input [int]
See the int listing.

### (inlet4)

#### Arguments

input [int]
See the int listing.

### (inlet5)

#### Arguments

input [int]
See the int listing.

### (inlet6)

#### Arguments

input [int]
See the int listing.

### (inlet7)

#### Arguments

input [int]
See the int listing.

### (inlet8)

#### Arguments

input [int]
See the int listing.

### (inlet9)

#### Arguments

input [int]
See the int listing.

### float

#### Arguments

input [float]
The number in each inlet will be stored in place of the \$f or \$i argument associated with it. The number will be truncated by a \$i argument.

### (inlet1)

#### Arguments

input [float]
See the float listing.

### (inlet2)

#### Arguments

input [float]
See the float listing.

### (inlet3)

#### Arguments

input [float]
See the float listing.

### (inlet4)

#### Arguments

input [float]
See the float listing.

### (inlet5)

#### Arguments

input [float]
See the float listing.

### (inlet6)

#### Arguments

input [float]
See the float listing.

### (inlet7)

#### Arguments

input [float]
See the float listing.

### (inlet8)

#### Arguments

input [float]
See the float listing.

### (inlet9)

#### Arguments

input [float]
See the float listing.

### set

#### Arguments

input [list]
If the word set precedes the items of a list received in the left inlet, the list of numbers are treated as if each had come in a different inlet, replacing the stored value with the new value. However, the expression is not evaluated and nothing is sent out the outlet. If there are fewer numbers in the message than there are inlets, the stored value in each remaining inlet stays unchanged.

### sm1

#### Arguments

table [list]
See the symbol listing.

### sm2

#### Arguments

table [list]
See the symbol listing.

### sm3

#### Arguments

table [list]
See the symbol listing.

### sm4

#### Arguments

table [list]
See the symbol listing.

### sm5

#### Arguments

table [list]
See the symbol listing.

### sm6

#### Arguments

table [list]
See the symbol listing.

### sm7

#### Arguments

table [list]
See the symbol listing.

### sm8

#### Arguments

table [list]
See the symbol listing.

### sm9

#### Arguments

table [list]
See the symbol listing.

### symbol

#### Arguments

table [list]
The word symbol, followed by the name of a table, will be stored in place of the \$s argument associated with that inlet, for accessing values stored in the table object.

### list

#### Arguments

input [list]
The items of a list received in the left inlet are treated as if each had come in a different inlet, and the expression is evaluated. If the list contains fewer items than there are inlets, the most recently received value in each remaining inlet is used. Any of the above messages in the left inlet will evaluate the expression and send out the result. If a value has never been received for each changeable argument, that value is considered 0 when the expression is evaluated. The number of inlets is determined by how many changeable arguments are typed in. The maximum number of inlets is 9.

## Output

### float

The output is the result of the evaluated expression.

### int

The output is the result of the evaluated expression.