com.vadelabs.toon.encode.arrays — com.vadelabs/toon 2026.01.05

Array encoding for TOON format.

Handles encoding of vectors with support for:

• Inline primitive arrays (key[N]: val1,val2,val3)
• Tabular arrays of objects (key[N]{col1,col2}: ...)
• Nested arrays of arrays

array-header clj/s

(array-header length delimiter)

Generates an array header with length information.

When delimiter is NOT comma, includes the delimiter in the header.

Parameters:

• length: Number of elements in the array
• delimiter: Delimiter character being used

Returns: String like "[3]" or "[3|]" or "[3 ]"

Examples: (array-header 3 ",") ;=> "[3]" (array-header 3 "|") ;=> "[3|]" (array-header 3 "\t") ;=> "[3\t]"

encode clj/s

(encode arr delimiter depth writer)

Encodes a vector to TOON format based on its contents.

Dispatch logic:

• Empty array: []
• Array of primitives: inline format
• Array of objects: tabular format
• Array of arrays: nested format

Parameters:

• array: Vector to encode
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

extract-common-keys clj/s

(extract-common-keys objects)

Extracts common keys from an array of objects.

Returns keys that appear in all objects, in the order they appear in the first object.

Uses set intersection for O(n×k) performance instead of O(n×k²).

Parameters:

• objects: Vector of maps

Returns: Vector of common keys (as strings)

Examples: (extract-common-keys [{"a" 1 "b" 2} {"a" 3 "b" 4}]) ;=> ["a" "b"]

inline clj/s

(inline values delimiter depth writer)

Encodes an array of primitives as an inline comma-separated list.

Format (depth > 0): val1,val2,val3 Format (depth = 0): [N]: val1,val2,val3

Parameters:

• values: Vector of primitive values
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter with inline array content.

Examples: [1,2,3] at depth > 0 → "1,2,3" [1,2,3] at depth = 0 → "[3]: 1,2,3" ["a","b","c"] → "a,b,c"

mixed clj/s

(mixed arr delimiter depth writer)

Encodes a mixed array with header using list item markers.

Format: [N]:

• value1
• value2

Parameters:

• array: Vector with mixed types
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

mixed-items clj/s

(mixed-items arr delimiter depth writer)

Encodes mixed array items without a header.

Format (items only, no header):

• value1
• value2
• [N]: nested array

Parameters:

• array: Vector with mixed types
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

object-as-list-item clj/s

(object-as-list-item obj delimiter depth writer)

(object-as-list-item obj delimiter depth writer encode-object-fn)

Encodes an object as a list item (v3.0 spec compliant).

For objects where first field is a tabular array:

• key[N]{fields}: row1 row2 other-key: value

For objects with primitive first field:

• key: value other-key: other-value

For empty objects:

Parameters:

• obj: Map to encode
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance
• encode-object-fn: (optional) Function to encode nested objects

Returns: Updated LineWriter.

of-arrays clj/s

(of-arrays arrays delimiter depth writer)

Encodes a nested array (array of arrays) with header using list format.

Format: N:

Parameters:

• arrays: Vector of vectors
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

of-arrays-items clj/s

(of-arrays-items arrays delimiter depth writer)

Encodes array of arrays items without a header.

Format (items only, no header):

Parameters:

• arrays: Vector of vectors
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

tabular clj/s

(tabular objects delimiter depth writer)

Encodes an array of objects in tabular format.

Format: [N]{col1,col2}: val1,val2 val3,val4

Parameters:

• objects: Vector of maps with common keys
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

tabular-header clj/s

(tabular-header cnt ks delimiter depth writer)

Encodes the header for a tabular array.

Format (depth > 0): [N]{col1,col2,...}: Format (depth = 0): [N]{col1,col2,...}:

Parameters:

• count: Number of objects in array
• keys: Vector of column names
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.

tabular-row clj/s

(tabular-row obj ks delimiter depth writer)

Encodes a single row in a tabular array.

Extracts values for the specified keys and encodes them.

Parameters:

• obj: Map representing one object
• keys: Vector of keys to extract
• delimiter: Delimiter character
• depth: Current indentation depth
• writer: LineWriter instance

Returns: Updated LineWriter.