Calculation field
The values in Calculation fields are calculated from the expressions specified by you in Memento Script, defined herein.
The following types of expressions are supported:
 Numeric
 Expressions involving numbers
 String
 Strings can also be added together, compared, etc
 Boolean
 Expressions that evaluate to true (1.0) and false (0.0)
Numeric and string types can not be mixed in a left / right operand pair.
Result type
For each calculation, there must be a correct result type set:
 Real result and Integer result
 are used for expressions with a numerical result
 Date/Time result
 is used to represent the result in the form of date and time. The calculation result is interpreted as the number of seconds that has passed since January 1, 1970 (UNIX time).
 Date result
 is the same as the previous type, but displays only the date
 String result
 is used for expressions that contain string manipulations or functions that return a string
Field value references and other variables
The values of other fields in the same entry and fields in linked libraries may be referenced by enclosing them within a hash mark and open brace #{ and a closed brace }. Other values can be referenced in similar fashion, such as the number of fields in an entry. These constitute readonly variables. For example, consider the following expression:
#{field name 1} + #{library 2.field name 2}
String values must be enclosed by singlequote (apostrophe) characters:
'Result: ' + '#{string field 1}' + '#{string field 2}'
Field references may be typed into the Expression area, or they may be inserted by pressing the +Field button and selecting from among the fields listed.
Values of variables cannot be changed by the Calculation field.
Operators
The following operators are supported:
Symbol  Operator  Description 

( ) 
open parenthesis closed parenthesis 
Grouping Group together a subexpression within an outer expression Example: (subexpression 1) + (subexpression 2) 
 + 
minus plus 
Unary number Example: 5 or +10 
+  
addition subtraction 
Binary Example: #{a} + #{b}  1 
* / 
multiplication division 
Binary Example: 6 / (8 * 13) 
%  modulo  Binary, integer remainder after division Example: #{months} % 12 
== != < <= > >= 
equal not equal less less or equal greater greater or equal 
Binary, relational Example: if( #{count} <= #{max} , #{count} , #{max} ) 
&&  
and or 
Binary, for TRUE and FALSE (Boolean) Example: if( #{Done}  ( #{Able} && #{Trying} ) , 'Raise' , 'No raise' ) 
!  not  Unary, for TRUE or FALSE (Boolean) Example: if( ! #{Done} , 'Work' , 'Relax' ) 
Functions
Functions are available to assist in crafting expressions to calculate a final result. Function calls may be typed into the expression, or the user may use the +Function button to display a tabbed list of functions that may be used.
 Note
 The rest of this section documents the available functions. However, while the functions may be better explained here, it may be incomplete or even incorrect. The menus of available functions within Memento when using the +Function button are quite useful and will always be more recently updated than what is documented here.
Math functions
Unless otherwise specified, all numbers are real numbers.
Function  Arguments  Returns 

abs  number  Absolute value of number 
acos  radians  Arc cosine of the angle 
asin  radians  Arc sine of the angle 
atan  radians  Arc tangent of the angle 
atan2  x, y  Arc tangent of an angle, given its rectangular coordinates 
ceil  number  Ceiling value of number 
cos  radians  Cosine of the angle 
exp  integer  Exponential number e raised to the power of integer 
floor  number  Floor value of number 
log  number  Natural logarithm (base e) of number 
max  number1, number2  The maximum value of number1 & number2 
min  number1, number2  The minimum value of number1 and number2 
pow  number, integer  number raised to the power of integer 
rint  real  real adjusted to the closest integer, returned as a real 
round  real  Closest integer to real 
sin  radians  Sine of the angle 
sqrt  number  Square root of number 
tan  radians  Tangent of the angle 
toDegrees  radians  Angle in degrees 
toRadians  degrees  Angle in radians 
Date/Time Functions
Function  Arguments  Returns 

datediff  date1, date2  Number of days between the 2 dates (date2  date1) 
dateadd 4 arguments 
date, intervalDays, intervalMonths, intervalYears 
date incremented by the date interval 
dateadd 7 arguments 
date, intervalSeconds, intervalMinutes, intervalHours, intervalDays, intervalMonths, intervalYears 
date incremented by the time interval 
formatDate  seconds  Equivalent date string (seconds since start of Jan 1 1970) 
formatDateTime  seconds  Equivalent date/time string (seconds since start of Jan 1 1970) 
formatTime  seconds  Equivalent time string (seconds since start of Jan 1 1970) 
now  The current time in seconds since the start of Jan 1 1970 Uses Universal Time (UTC) regardless of local settings or time zone  
relativeTimeStr  startTime  String describing the elapsed time since the given start time 
formatDuration  seconds  Duration as a string formatted as MM:SS or H:MM:SS 
String functions
Regarding string functions, an index is the relative number of a character within the string. The first string character has index 0 (zero).
Function  Arguments  Returns 

numToStr  number  String representation of number 
compareTo  string1, string2 
Zero, if the strings are equal A negative number, if string1 < string2 A positive number, if string1 > string2 
compareToIgnoreCase  string1, string2 
Zero, if the strings are equal (ignoring case) A negative number, if string1 < string2 (ignoring case) A positive number, if string1 > string2 (ignoring case) 
concat  string1, string2 
String of string2 appended to the end of string1
concat(#{name}, ', Jr.') 
endsWith  string1, string2 
TRUE (1.0), if string1 ends with string2 FALSE (0.0), if it doesn't 
equals  string1, string2 
TRUE (1.0), if the strings are identical FALSE (0.0), if not 
equalsIgnoreCase  string1, string2 
TRUE (1.0), if the strings are identical (ignoring case) FALSE (0.0), if not 
indexOf  string1, string2, index 
Within string1 from index to the end, the index of the next occurrence of string2 1, if no more occurrences next = indexOf(#{Description}, ' and ', next) 
length  string  Length of (number of characters in) string 
replace  string, char1, char2 
String of string with all matching char1s replaced with char2s
replace(#{Description}, ';', '.') 
startsWith  string1, string2, index 
TRUE (1.0), if string1, starting at position index, starts with string2 FALSE (0.0), if it doesn't 
substring  string, startIndex, endIndex 
The substring of string that starts at startIndex and ends at endIndex 
toLowerCase  string  The string string with all uppercase characters converted to lowercase 
toUpperCase  string  The string string with all lowercase characters converted to uppercase 
trim  string  The string string with all "white space" (blanks, tabs, etc) removed from both ends 
Logical functions
Function  Arguments  Returns 

if  expression, valueIfTrue, valueIfFalse 
One value if a logical expression is TRUE (not equal to 0.0) and another if it is FALSE (equal to 0.0) Read it as "If expression is true, then valueIfTrue, else valueIfFalse" if(#{remaining} == 0, 'Done', 'Incomplete') 
switch  expression, valueResultPairs, defaultResult 
1+(2*#pairs)+1 arguments The final result based on matching expression against the paired values to identify the paired result (or else defaultResult) to be used switch(#{count},
1, 'One',
2, 'Two',
'Many') 
Accessing values of linked library entries
Use the following syntax to get access to the values of Link to Entry and other linking fields:
#{link field name.linked field name}
where link field name is the name of a Link to Entry field, linked field name is the name of a field of a related entry.
You can select a field, including one from a related library, using the +Field button.
If a link field contains several links, then use an index (starting from zero) to get access to them:
#{link field name@0.linked field name}, #{link field name@1.linked field name}, …
You can specify one of the supported aggregation functions instead of the index:
#{link field name@sum.linked field name}
This expression returns the sum of values of field linked field name for all entries included into link field name. The functions supported are: sum, avg, min, and max.
Use the following syntax to get the number of entries in the library referenced by link field name:
#{link field name@size}
Link example: Parents and children
Parents contains fields Name and Age. Children has fields Name and Parents (link to entry (manytomany)).
Add field "Average parent age" (calculation, real, scale 1) to Children and select the related field from the +Field list: parents.age. Then insert "@avg", making it:
#{parents@avg.age}
Link example: Orders of products
Products has fields SKU, Description, and Price. Orders has fields #, Date, Customer (link to entry (onetomany)), and Products (link to entry (manytomany)).
Add field "Total" (calculation, real, scale 2) to Orders and select the related field from the +Field list: products.price. Then insert "@sum", making it:
#{products@sum.price}
Note: This example points out a deficiency in using a manytomany relationship for orders of products (or of services). One would hope to associate a quantity for each product ordered, but that requirement cannot be met with this 3library technique. So, in real life, order solutions generally involve 4 libraries: Customers, Products, Orders, and Order Items. The quantity can reside in Order Items.
Examples
Example: Singleoperator expression
Entries contain fields: Price, Count
We add a Calculation field Sum by using the following expression:
#{Price} * #{Count}
Example: Percentage
Entries contain fields: Count, Total
We add a Calculation field Percentage by using the following expression:
(#{Count } / #{ Total }) * 100
Example: Duration
Entries contain fields: StartDateTime, EndDateTime
We add a Calculation field Duration by using the following expression (result is the number of seconds):
#{EndDateTime}  #{StartDateTime}
Example: Days
Entries contain fields: StartDate, EndDate
We add a Calculation field Days by using the following expression:
datediff(#{StartDate}, #{EndDate})
Example: Days left
Entries contain field: Time
We add a Calculation field Days Left by using the following expression:
if( #{Time} > now() , rint((#{Time}  now())/(60*60*24)) , 'in the past' )
Example: References
There’s a library Order containing orders and a library Item containing items. Library Order contains a link to library Item and a numeric field Count. Library Item contains field Price.
To calculate the cost of the order, add Calculation field Sum using the following formula:
#{count} * #{item.price}
If an order can make a reference to several different items, their total cost can be calculated:
#{item@sum.price}
The most expensive item:
#{item@max.price}
The cheapest item:
#{item@min.price}
The average price for the item:
#{item@avg.price}
Aggregation functions in Calculation fields
Aggregation functions are used to process multiple values of fields of linked entries and return one value.
// This function returns the sum of values
// of the field called linked_field_name for all entries
// included in link_field_name.
$sum('link_field_name.linked_field_name')
Aggregation functions can be used with multiple field of a linked entry. In this case, a pairing operation is specified, which will be applied to the fields before the main aggregation function is applied.
// This function first multiplies the field1 and field2 fields
// of the linked entry of the link_field_name field.
// After that the resulting set of numbers is summed.
// The pairwise operation, in this case, is multiplication: '@mul'
$sum('link_field_name.field1', 'link_field_name.field2', '@mul')
Note that the function parameters are specified in single quotes.
Function  Arguments  Returns 

$sum  fields, operation (optional, used if multiple argument fields are specified)  fields &{mdash;} the identifier of the field or attribute of the linked entry in the format: 'link_field_name.linked_field_name'
If multiple attributes are received from the linked entries, the paired operation is performed before the summation takes place. The function returns the summation. The type of paired operation is defined by the last argument of the function operation(). The type of paired operation is determined by the last argument of the function operation()and can be one of the following:
The operation() argument is optional. If it is not specified, then the multiplication operation is used as a default. 
$avg  fields, operation  This function returns the average of values of field linked_field_name for all entries included into link_field_name. 
$min  fields, operation  This function returns the minimum of values of field linked_field_name for all entries included into link_field_name. 
$max  fields, operation  This function returns the maximum of values of field linked_field_name for all entries included into link_field_name. 
 Name
 Textual, caseinsensitive field identifier that can include spaces; it's best to avoid characters that can be used as operators, though (standard across all field types)
 Hint
 Textual, caseinsensitive field identifier that can include spaces
Advanced Parameters
 Thousands separators
 If the chosen result type is Integer or Real, use spaces as separators to break the value into thousands. By default, it will not.
Display Options
 Display in the list as
 Select among the following roles for the current field:
 As a Regular field
 As an Entry Name
 As an Entry Description
 As an Entry Status
 Use in Calendar as
 None / Duration, mins / Duration, hours
 The field name
 Display the name of the field in the card entry (By default, On). By this, it is meant that the field name will or will not be displayed on either the Entry View card or the Entry Edit card.
 Font
 Choices are:
 Family: Regular, Light, Condensed, Thin, Medium. By default, Regular.
 Style: Normal, Bold, Italic, Bold Italic. By default, Normal.
 Size: By default, 18. Direct entry to change.
 Color: By default, White. Palette of 20 colors, backed up by a continuously variable color chooser.
 Dependencies
 Ability to add one or more visibility dependencies upon fields with qualifying types.
Comparison with using a Memento JavaScript field
Using a JavaScript field instead of a Calculation field is slightly more involved, due to the fact that unlike a Calculation field, as of this writing, there is no provision to look up a list of JavaScript functions and include them by selection from the list. The other differences are minor.
Whereas in a Calculation field, the value of another field in the library can be referenced by:
#{fieldname}
In a JavaScript field, the same reference would be:
field(fieldname)
So, a script to multiply two fields, such as quantity and price, instead of #{quantity} * #{price}, you would have field("quantity") * field("price")
Calling functions
The essential remaining difference is the functions that are available, the way general functions are called, and the way functions specific to the field's type (referred to as the type's methods) are called.
In JavaScript, there are two kinds of functions. The first is just like Calculation field functions, except that JavaScript has its own generally different functions to do the same things. For example, to return the maximum of two fields in a Calculation field would be max(#{field1},#{field2}
, while in JavaScript, you would have Math.max(field("field1"), field("field2"))
.
Then there are unary JavaScript functions that are specific to the type of field. These functions may be called in this same way, such as Math.round(field("field1"))
. In JavaScript, there is an alternate way to specify it, which can come in very handy in some cases, and that is field("field1").round()
. When written this way, round()
is referred to as a method rather than as a function. The distinction is minor. It is essentially the same as a function, except for the way it is written.
Operators in Memento JavaScript
The following operators are supported:
Symbol  Operator  Description 

( ) 
open parenthesis closed parenthesis 
Grouping Group together a subexpression within an outer expression Example: (subexpression 1) + (subexpression 2) 
 + 
minus plus 
Unary number Example: 5 or +10 
+  
addition subtraction 
Binary Example: #{a} + #{b}  1 
* / 
multiplication division 
Binary Example: 6 / (8 * 13) 
%  modulo  Binary, integer remainder after division Example: #{months} % 12 
== != < <= > >= 
equal not equal less less or equal greater greater or equal 
Binary, relational Example: if( field("count") <= field("max") , field("count") , field("max") ) 
&&  
and or 
Binary, for TRUE and FALSE (Boolean) Example: if( field("Done")  ( field("Able") && field("Trying") ) , 'Raise' , 'No raise' ) 
!  not  Unary, for TRUE or FALSE (Boolean) Example: if( ! field("Done") ) 'Work' else 'Relax' ) 
Functions and methods of Memento JavaScript
Functions are available to assist in crafting expressions to calculate a final result. Function calls may be typed into the expression, or the user may use the +Function button to display a tabbed list of functions that may be used.
 Note
 The rest of this section documents the available functions. However, while the functions may be better explained here, it may be incomplete or even incorrect. The menus of available functions within Memento when using the +Function button are quite useful and will always be more recently updated than what is documented here.
Math functions
Unless otherwise specified, all numbers are real numbers. As a general case, when the table refers to a variable, a field value reference may be used instead, such as field(fieldname)
or field("MyField")
.
Function  Arguments  Returns  Function example  Method example 

abs 
number  Absolute value of number  Math.abs(delta) 
delta.abs()

acos 
radians  Arc cosine of the angle  
asin 
radians  Arc sine of the angle  
atan 
radians  Arc tangent of the angle  
atan2 
x, y  Arc tangent of an angle, given its rectangular coordinates  
ceil 
number  Ceiling value of number  
cos 
radians  Cosine of the angle  
exp 
integer  Exponential number e raised to the power of integer  
floor 
number  Floor value of number  
log 
number  Natural logarithm (base e) of number  
max 
number1, number2  The maximum value of number1 & number2  
min 
number1, number2  The minimum value of number1 and number2  
pow 
number, integer  number raised to the power of integer  
rint 
real  real adjusted to the closest integer, returned as a real  
round 
real  Closest integer to real  
sin 
radians  Sine of the angle  
sqrt 
number  Square root of number  
tan 
radians  Tangent of the angle  
toDegrees 
radians  Angle in degrees  
toRadians 
degrees  Angle in radians 
Date/Time Functions
Function  Arguments  Returns 

datediff  date1, date2  Number of days between the 2 dates (date2  date1) 
dateadd 4 arguments 
date, intervalDays, intervalMonths, intervalYears 
date incremented by the date interval 
dateadd 7 arguments 
date, intervalSeconds, intervalMinutes, intervalHours, intervalDays, intervalMonths, intervalYears 
date incremented by the time interval 
formatDate  seconds  Equivalent date string (seconds since start of Jan 1 1970) 
formatDateTime  seconds  Equivalent date/time string (seconds since start of Jan 1 1970) 
formatTime  seconds  Equivalent time string (seconds since start of Jan 1 1970) 
now  The current time in seconds since the start of Jan 1 1970 Uses Universal Time (UTC) regardless of local settings or time zone  
relativeTimeStr  startTime  String describing the elapsed time since the given start time 
formatDuration  seconds  Duration as a string formatted as MM:SS or H:MM:SS 
String functions
Regarding string functions, an index is the relative number of a character within the string. The first string character has index 0 (zero).
Function  Arguments  Returns 

numToStr  number  String representation of number 
compareTo  string1, string2 
Zero, if the strings are equal A negative number, if string1 < string2 A positive number, if string1 > string2 
compareToIgnoreCase  string1, string2 
Zero, if the strings are equal (ignoring case) A negative number, if string1 < string2 (ignoring case) A positive number, if string1 > string2 (ignoring case) 
concat  string1, string2 
String of string2 appended to the end of string1
concat(#{name}, ', Jr.') 
endsWith  string1, string2 
TRUE (1.0), if string1 ends with string2 FALSE (0.0), if it doesn't 
equals  string1, string2 
TRUE (1.0), if the strings are identical FALSE (0.0), if not 
equalsIgnoreCase  string1, string2 
TRUE (1.0), if the strings are identical (ignoring case) FALSE (0.0), if not 
indexOf  string1, string2, index 
Within string1 from index to the end, the index of the next occurrence of string2 1, if no more occurrences next = indexOf(#{Description}, ' and ', next) 
length  string  Length of (number of characters in) string 
replace  string, char1, char2 
String of string with all matching char1s replaced with char2s
replace(#{Description}, ';', '.') 
startsWith  string1, string2, index 
TRUE (1.0), if string1, starting at position index, starts with string2 FALSE (0.0), if it doesn't 
substring  string, startIndex, endIndex 
The substring of string that starts at startIndex and ends at endIndex 
toLowerCase  string  The string string with all uppercase characters converted to lowercase 
toUpperCase  string  The string string with all lowercase characters converted to uppercase 
trim  string  The string string with all "white space" (blanks, tabs, etc) removed from both ends 
Logical functions
Function  Arguments  Returns 

if  expression, valueIfTrue, valueIfFalse 
One value if a logical expression is TRUE (not equal to 0.0) and another if it is FALSE (equal to 0.0) Read it as "If expression is true, then valueIfTrue, else valueIfFalse" if(#{remaining} == 0, 'Done', 'Incomplete') 
switch  expression, valueResultPairs, defaultResult 
1+(2*#pairs)+1 arguments The final result based on matching expression against the paired values to identify the paired result (or else defaultResult) to be used switch(#{count},
1, 'One',
2, 'Two',
'Many') 