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Built-in Functions

DocStencil provides many builtin functions for common tasks. All builtin functions are $-prefixed.

Formatting​

$format​

Format dates and numbers with patterns:

{$format(date, "yyyy-MM-dd")}        // 2024-03-15
{$format(date, "MMMM dd, yyyy")}     // March 15, 2024
{$format(number, "0.00")}            // 3.14
{$format(number, "#,##0.00")}        // 1,234.56

Uses Java's DateTimeFormatter for dates and DecimalFormat for numbers.

$formatDate​

Format dates explicitly:

{$formatDate(invoice.date, "MMMM dd, yyyy")}

$formatNumber​

Format numbers explicitly:

{$formatNumber(price, "#,##0.00")}

Collections​

$filter​

Filter items by a predicate:

{$filter(items, (x) => x.active)}
{items | $filter((x) => x.price > 100)}

$map​

Transform each item:

{$map(users, (u) => u.name)}
{users | $map((u) => u.email)}

$reduce​

Reduce a collection to a single value:

{$reduce(numbers, (sum, n) => sum + n, 0)}
{items | $reduce((total, item) => total + item.price, 0)}

$sum​

Sum up numbers:

{$sum(numbers)}
{items | $sum()}

$filterNotNull​

Remove null values from a collection:

{$filterNotNull(items)}

$enumerate​

Wrap items with index and position info:

{for item in $enumerate(items)}
  {item.index}: {item.value.name}
{end}

Each wrapped item has:

  • value: the original item
  • index: zero-based position (0, 1, 2, ...)
  • isFirst / isLast: boolean flags
  • isEven / isOdd: boolean flags based on index

$reverse​

Reverse a collection:

{$reverse(items)}

$range​

Generate a sequence of numbers:

{$range(5)}         // 0, 1, 2, 3, 4
{$range(1, 5)}      // 1, 2, 3, 4

$join​

Join items with a separator:

{$join(names, ", ")}              // Alice, Bob, Charlie
{names | $join(" | ")}            // Alice | Bob | Charlie

Type Casting​

Convert values between numeric types:

{$asByte(value)}
{$asShort(value)}
{$asInt(value)}
{$asLong(value)}
{$asFloat(value)}
{$asDouble(value)}

Utilities​

$now​

Get the current date and time:

{$format($now(), "yyyy-MM-dd HH:mm")}

$notNull​

Check if a value is not null (returns boolean):

{if $notNull(user.email)}
  Email: {user.email}
{end}