Type Information Functions
typeof
Description: Returns the type code of a value. Arguments:
value: The value to get the type of
Returns: An integer representing the type code of the value
length
Description: Returns the length of a sequence (string, list, map). Arguments:
sequence: The sequence to measure
Returns: An integer representing the length of the sequence
Note: Will raise an error if the value is not a sequence type.
Type Conversion Functions
tostr
Description: Converts value(s) to a string representation.
Arguments:
value1, value2, ...: One or more values to convert to string
Returns: A string representation of the concatenated values
Note: If multiple arguments are provided, they are concatenated together.
tosym
Description: Converts a scalar value to a symbol.
Arguments:
value: The value to convert (must be a string, boolean, error, or symbol)
Returns: A symbol representing the value
Note: Will raise E_TYPE if the value cannot be converted to a symbol.
toliteral
Description: Converts a value to its literal string representation.
Arguments:
value: The value to convert
Returns: A string containing the literal representation of the value
Note: This produces a string that could be evaluated to recreate the original value.
toint
Description: Converts a value to an integer.
Arguments:
value: The value to convert (must be a number, object, string, or error)
Returns: The integer representation of the value
Note: String conversion parses the string as a number; invalid strings convert to 0.
tonum
Alias for toint. Description:
toobj
Description: Converts a value to an object reference.
Arguments:
value: The value to convert (must be a number, string, or object)
Returns: An object reference
Note: For strings, accepts formats like "123" or "#123". Invalid strings convert to object #0.
tofloat
Description: Converts a value to a floating-point number.
Arguments:
value: The value to convert (must be a number, string, or error)
Returns: The floating-point representation of the value
Note: String conversion parses the string as a number; invalid strings convert to 0.0.
Comparison Functions
equal
Description: Performs a case-sensitive equality comparison between two values.
Arguments:
value1: First value to comparevalue2: Second value to compare
Returns: Boolean result of the comparison (true if equal, false otherwise)
JSON Conversion Functions
generate_json
str generate_json(value [, str mode])
Returns the JSON representation of the MOO value.
MOO supports a richer set of values than JSON allows. The optional mode specifies how this function handles the conversion of MOO values into their JSON representation.
The common subset mode, specified by the literal mode string "common-subset", is the default conversion mode. In this mode, only the common subset of types (strings and numbers) are translated with fidelity between MOO types and JSON types. All other types are treated as alternative representations of the string type. This mode is useful for integration with non-MOO applications.
The embedded types mode, specified by the literal mode string "embedded-types", adds type information. Specifically, values other than strings and numbers, which carry implicit type information, are converted into strings with type information appended. The converted string consists of the string representation of the value (as if tostr() were applied) followed by the pipe (|) character and the type. This mode is useful for serializing/deserializing objects and collections of MOO values.
generate_json([]) => "{}"
generate_json(["foo" -> "bar"]) => "{\"foo\":\"bar\"}"
generate_json(["foo" -> "bar"], "common-subset") => "{\"foo\":\"bar\"}"
generate_json(["foo" -> "bar"], "embedded-types") => "{\"foo\":\"bar\"}"
generate_json(["foo" -> 1.1]) => "{\"foo\":1.1}"
generate_json(["foo" -> 1.1], "common-subset") => "{\"foo\":1.1}"
generate_json(["foo" -> 1.1], "embedded-types") => "{\"foo\":1.1}"
generate_json(["foo" -> #1]) => "{\"foo\":\"#1\"}"
generate_json(["foo" -> #1], "common-subset") => "{\"foo\":\"#1\"}"
generate_json(["foo" -> #1], "embedded-types") => "{\"foo\":\"#1|obj\"}"
generate_json(["foo" -> E_PERM]) => "{\"foo\":\"E_PERM\"}"
generate_json(["foo" -> E_PERM], "common-subset") => "{\"foo\":\"E_PERM\"}"
generate_json(["foo" -> E_PERM], "embedded-types") => "{\"foo\":\"E_PERM|err\"}"
JSON keys must be strings, so regardless of the mode, the key will be converted to a string value.
generate_json([1 -> 2]) => "{\"1\":2}"
generate_json([1 -> 2], "common-subset") => "{\"1\":2}"
generate_json([1 -> 2], "embedded-types") => "{\"1|int\":2}"
generate_json([#1 -> 2], "embedded-types") => "{\"#1|obj\":2}"
Warning: generate_json does not support WAIF or ANON types.
parse_json
value parse_json(str json [, str mode])
Returns the MOO value representation of the JSON string.
If the specified string is not valid JSON, E_INVARG is raised.
The optional mode specifies how this function handles conversion of MOO values into their JSON representation. The options are the same as for generate_json().
parse_json("{}") => []
parse_json("{\"foo\":\"bar\"}") => ["foo" -> "bar"]
parse_json("{\"foo\":\"bar\"}", "common-subset") => ["foo" -> "bar"]
parse_json("{\"foo\":\"bar\"}", "embedded-types") => ["foo" -> "bar"]
parse_json("{\"foo\":1.1}") => ["foo" -> 1.1]
parse_json("{\"foo\":1.1}", "common-subset") => ["foo" -> 1.1]
parse_json("{\"foo\":1.1}", "embedded-types") => ["foo" -> 1.1]
parse_json("{\"foo\":\"#1\"}") => ["foo" -> "#1"]
parse_json("{\"foo\":\"#1\"}", "common-subset") => ["foo" -> "#1"]
parse_json("{\"foo\":\"#1|obj\"}", "embedded-types") => ["foo" -> #1]
parse_json("{\"foo\":\"E_PERM\"}") => ["foo" -> "E_PERM"]
parse_json("{\"foo\":\"E_PERM\"}", "common-subset") => ["foo" -> "E_PERM"]
parse_json("{\"foo\":\"E_PERM|err\"}", "embedded-types") => ["foo" -> E_PERM]
In embedded types mode, key values can be converted to MOO types by appending type information. The full set of supported types are obj, str, err, float and int.
parse_json("{\"1\":2}") => ["1" -> 2]
parse_json("{\"1\":2}", "common-subset") => ["1" -> 2]
parse_json("{\"1|int\":2}", "embedded-types") => [1 -> 2]
parse_json("{\"#1|obj\":2}", "embedded-types") => [#1 -> 2]
Note: JSON converts
nullto the string "null".
Warning: WAIF and ANON types are not supported.
Memory Functions
value_bytes
Description: Returns the size of a value in bytes.
Arguments:
value: The value to measure
Returns: The size of the value in bytes
object_bytes
Description: Returns the size of an object in bytes.
Arguments:
object: The object to measure
Returns: The size of the object in bytes
Note: This includes all properties, verbs, and other object data.
Note: Most of these functions follow a consistent pattern of validating arguments and providing appropriate error
handling. Type conversion functions generally attempt to convert intelligently between types and provide sensible
defaults or errors when conversion isn't possible.
Error Handling Functions
error_message
Description: Returns the error message associated with an error value.
Arguments:
error: The error value to get the message from
Returns: The error message string
error_code
Description: Strips off the message from an error value and returns just the error without it.
Arguments:
error: The error value to get the code from
Returns: The error code of the error value