At some point between R2015a and R2016b, Matlab switched from using the TC.xml file to a more flexible and readable JSON implementation. Tab-completion information is now stored in a functionSignatures.json file located in the same directory as the relevant function's m-file. This also means you no longer have to hack Matlab root files in order to enjoy tab completion.
The function signatures file has the general form:
{
"FunctionName1":
{
"key1":"val1",
"key2":"val2",
"keyn":"valn"
},
"FunctionName2":
{
"key1":"val1",
"key2":"val2",
"keyn":"valn"
}
}
A number of keys are supported including "platform", "setsAns", "inputs", and "outputs", although inputs and outputs are by far the most common. Both of these keys take an array of objects that describe the input / output variable(s) and how to tab complete them.
The objects typically take one of the following forms:
{"name":"variable_name", "kind":"kind_option", "type":"string_or_array_of_type"}
{"mutuallyExclusiveGroup":
[
...
]
}
{"name":"varargin", "kind":"optional", "multiplicity":"append"}
The value for "kind" can include (but may not be limited to) "required", "optional", and "namevalue". The value for "type" can be a string such as "filepath" for tab completion of files, or a more complicated JSON array. Examples can be found in matlabroot/toolbox/matlab. It appears that matlabroot/toolbox/matlab/imagesci/functionSignatures.json has a particularly rich set of examples on how to do auto-completion. Here are entries for two functions that I cherry-picked from that file:
...
"h5read":
{
"inputs":
[
{"name":"filename", "kind":"required", "type":"filepath"},
{"name":"varargin", "kind":"optional", "multiplicity":"append"}
]
},
...
"imread":
{
"inputs":
[
{"mutuallyExclusiveGroup":
[
{"name":"filename", "kind":"required", "type":[["filepath=*.cur,*.ico,*.gif,*.hdf"], ["matlabpath=*.cur,*.ico,*.gif,*.hdf"]]},
[
{"name":"filename", "kind":"required", "type":[["char"], ["filepath"]]},
{"name":"fmt", "kind":"required", "type":["char", "choices={'cur','ico','gif','hdf'}"]}
]
]
},
{"name":"idx", "kind":"optional", "type":["numeric", "vector", ">=1"]}
],
"outputs":
[
{"name":"A", "type":[["numeric", "2d"], ["numeric", "3d"]]}
]
},
...
