Built-in Functions
All 80+ standard DMN 1.5 built-in functions are supported, plus a set of practical extensions.
Conversion
| Function | Description |
|---|---|
string(value) | Convert any value to string |
string(number, picture) | Format number with XPath 2.0 picture mask |
number(string, groupSep?, decSep?) | Parse string to number |
string join(list, delimiter?, prefix?, suffix?) | Join string list |
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string(42) // "42"
string(1234.5, "##,##0.00") // "1,234.50"
string(7, "000") // "007"
string(0.1234, "0.00%") // "12.34%"
number("1,234.56", ",", ".") // 1234.56
string join(["a","b","c"], "-") // "a-b-c"String
| Function | Description |
|---|---|
string length(string) | Unicode code-point length |
substring(string, start, length?) | 1-based, supports negative start |
substring before(string, match) | Text before first match |
substring after(string, match) | Text after first match |
upper case(string) | Uppercase |
lower case(string) | Lowercase |
trim(string) | Strip whitespace |
contains(string, match) | Substring check |
starts with(string, match) | Prefix check |
ends with(string, match) | Suffix check |
matches(input, pattern, flags?) | XPath 2.0 regex match |
replace(input, pattern, replacement, flags?) | Regex replace |
split(string, delimiter) | Split by regex |
extract(input, pattern) | Find all regex matches |
pad left(string, length, char?) | Left-pad string |
pad right(string, length, char?) | Right-pad string |
encode for URI(string) | URI encode |
decode for URI(string) | URI decode |
is blank(string) | true if null, empty, or whitespace-only |
to base64(string) | Base64-encode a string |
from base64(string) | Base64-decode a string |
string format(template, args...) | Interpolate {} placeholders in order |
to json(value) | Serialize any FEEL value to a JSON string |
from json(string) | Parse a JSON string into a FEEL value |
Numeric
| Function | Description |
|---|---|
decimal(n, scale) | Round to scale (HALF_EVEN/banker's rounding) |
floor(n, scale?) | Round toward −∞ |
ceiling(n, scale?) | Round toward +∞ |
round up(n, scale) | Round away from zero |
round down(n, scale) | Round toward zero |
round half up(n, scale) | Round 0.5 away from zero |
round half down(n, scale) | Round 0.5 toward zero |
abs(n) | Absolute value (works on durations too) |
modulo(dividend, divisor) | Modulo (result has sign of divisor) |
sqrt(number) | Square root |
log(number) | Natural logarithm |
exp(number) | e^n |
odd(number) | Is odd integer? |
even(number) | Is even integer? |
random number() | Random in [0, 1) |
List
| Function | Description |
|---|---|
list contains(list, element) | Membership test |
count(list) | Number of elements |
min(list) | Minimum value |
max(list) | Maximum value |
sum(list) | Sum of numbers |
mean(list) | Arithmetic mean |
median(list) | Middle value |
stddev(list) | Sample standard deviation |
mode(list) | Most frequent value(s) |
product(list) | Product of numbers |
all(list) | All truthy? |
any(list) | Any truthy? |
append(list, item...) | Add items |
concatenate(list...) | Merge lists |
insert before(list, pos, item) | Insert at position |
remove(list, pos) | Remove at position |
reverse(list) | Reverse order |
index of(list, match) | All positions of match |
sublist(list, start, length?) | Slice |
flatten(list) | Deep flatten |
distinct values(list) | Remove duplicates |
duplicate values(list) | Values that appear more than once |
union(list...) | Merge with deduplication |
sort(list, comparator?) | Sort |
list replace(list, pos/fn, value) | Replace by position or predicate |
is empty(list) | true if null or empty list |
partition(list, size) | Split into fixed-size sublists |
Context
| Function | Description |
|---|---|
get value(context, key) | Get value by key string |
get entries(context) | List of {key, value} entries |
context(entries) | Build context from entry list |
context put(context, key, value) | Add/overwrite key |
context merge(list) | Merge context list |
Null / Error handling
| Function | Description |
|---|---|
get or else(value, default) | Return value if non-null, otherwise default |
error(message) | Return null and emit an EXPLICIT_ERROR warning |
assert(condition, message) | Return true or null + ASSERTION_FAILED warning |
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get or else(null, "fallback") // "fallback"
get or else(42, 0) // 42
if score < 0 then error("score negative") else score * 1.5
assert(x > 0, "x must be positive") // null + warning when x <= 0Misc
| Function | Description |
|---|---|
uuid() | Generate a UUID v4 string |
Boolean
| Function | Description |
|---|---|
is(value1, value2) | Structural equality (same type and value) |
Range
before, after, meets, met by, overlaps, overlaps before, overlaps after, includes, during, starts, started by, finishes, finished by, coincides
Number formatting
format number(n, picture, locale?) formats a number using an XPath 2.0-style picture mask.
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format number(1234.56, "#,##0.00") // "1,234.56"
format number(42, "000") // "042"
format number(0.1234, "0.00%") // "12.34%"
format number(1234.56, "$#,##0.00") // "$1,234.56"
format number(1000000, "#,##0") // "1,000,000"
format number(42.7, "0") // "43" (rounded)
format number(1.5, "0.##") // "1.5" (# = optional digit)With a locale, the decimal/grouping separators are swapped for comma-decimal conventions (pt-BR, de, fr, es, it…):
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format number(1234567.89, "#,##0.00", "pt-BR") // "1.234.567,89"
format number(1234.56, "#,##0.00", "de") // "1.234,56"
format number(1234.56, "#,##0.00", "en-US") // "1,234.56"Negative numbers prepend - automatically (or use a semicolon to provide an explicit negative subpicture):
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format number(-1234.56, "#,##0.00") // "-1,234.56"
format number(-1234.56, "#,##0.00;(#,##0.00)") // "(1,234.56)"Temporal
See Temporal for full reference including format date, format time, and format date and time.