Module value
Boxing and Unboxing Primitive Types.
All llib objects are by defiintion values; primitive types like ints (long long) ,
floats (double) and bools must be boxed first. Boxed types are pointers-to-primitive,
which are not arrays; value_is_box becomes true. To box a value use value_int,
value_float and value_bool; to check the type use the equivalent value_is_TYPE
functions, and to extract the value use value_as_TYPE.
Error values are strings with a distinct type, so we have value_error and value_is_error.
value_parse converts strings to values using a known value type; value_tostring will convert a value to a default string representation. More complicated value types like arrays don’t have a unique representation as strings, so see json_tostring and xml_tostring.
See test-json.c for how values are used in practice.
Querying Type
| value_is_box (v) | is this a boxed value? |
| value_is_string (v) | is this value a string? |
| value_is_error (v) | is this value an error string? |
| value_is_float (v) | does this value contain a double? |
| value_is_int (v) | does this value contain a long long? |
| value_is_bool (v) | does this value contain a bool? |
| value_is_simple_map (v) | does this value represent a simple map? |
Boxing Values
| value_error (msg) | make a error value. |
| value_float (x) | box a double. |
| value_int (i) | box a long long. |
| value_bool (i) | box a bool. |
Converting to and from Strings
| value_parse (str, type) | convert a string into a value of the desired type. |
| value_tostring (v) | Default representation of a value as a string. |
Querying Type
- value_is_box (v)
-
is this a boxed value?
Parameters:
- v PValue
Returns:
-
bool
- value_is_string (v)
-
is this value a string?
Parameters:
- v PValue
Returns:
-
bool
- value_is_error (v)
-
is this value an error string?
Parameters:
- v PValue
Returns:
-
bool
- value_is_float (v)
-
does this value contain a
double?Parameters:
- v PValue
Returns:
-
bool
- value_is_int (v)
-
does this value contain a
long long?Parameters:
- v PValue
Returns:
-
bool
- value_is_bool (v)
-
does this value contain a
bool?Parameters:
- v PValue
Returns:
-
bool
- value_is_simple_map (v)
-
does this value represent a simple map?
Parameters:
- v PValue
Returns:
-
bool
Boxing Values
- value_error (msg)
-
make a error value.
Parameters:
- msg const char *
Returns:
-
PValue
- value_float (x)
-
box a
double.Parameters:
- x double
Returns:
-
PValue
- value_int (i)
-
box a
long long.Parameters:
- i long long
Returns:
-
PValue
- value_bool (i)
-
box a
bool.Parameters:
- i bool
Returns:
-
PValue
Converting to and from Strings
- value_parse (str, type)
-
convert a string into a value of the desired type.
Parameters:
- str const char *
- type ValueType
Returns:
-
PValue
- value_tostring (v)
-
Default representation of a value as a string.
Only applies to scalar values (if you want to show arrays & maps
use json module).
Parameters:
- v PValue
Returns:
-
const char *