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Change-Id: I0b25fd1c645a47084fb7fda1bbb7d41a2d10dcbb

doc/source/protocol/history.rst

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+History
+=======
+
+Meeting 29.5.2017
+-----------------
+
+* for api: float is 'double'
+* everything countable is int64_t
+* description is string (UTF-8 without embedded \0) (zero terminated for API)
+* names / identifiers are:  [_a-z][_a-z0-9]{0,63}
+* BLOB is [length, string_encoding (base64 or json_string) ] ???
+* enum is transferred by value (api: int64_t)
+* basic data types: string, BLOB(maxsize), int, double, bool, enum(mapping)
+* encode as ["string"] ["blob"] ["int"] ["double"] ["bool"] ["enum", {<number_value>:<name>}]
+* send as json_string [length, json_string] number number 0_or_1 number_value
+* complex data types: array, tuple, struct
+* encode as: ["array", <subtype>] ["tuple", [<list_of_compositing data types>] ["struct", {"name_of_subcomponent":<type of subcomponent>}]
+* send as [array] [array} {mapping}
+* forbid: structs in structs, nesting level > 3, arrays may only contain basic types + tuple
+* essential features should not rely on complex data types
+* fallback: if ECS can not handle a non-basic datatype: handle as string containing the JSON-representation.
+* mandatory for all ECS: enum, int, double, string, bool, tuple(enum,string)
+
+Merge datatype and validator
+++++++++++++++++++++++++++++
+
+* ["enum", {<number_value>:<json_string>}]
+* ["int"] or ["int", <lowest_allowed_value>, <highest_allowed_value>]
+* ["double"] or ["double", <lowest_allowed_value>, <highest_allowed_value>]
+* ["bool"]
+* ["blob", <maximum_size_in_bytes>] or ["blob", <minimum_size_in_bytes>, <maximum_size_in_bytes>]
+* ["string", <maximum_allowed_length>] or ["string", <min_size>, <max_size>]
+* ["array", <basic_data_type>, <max_elements>] or ["array", <dtype>, <min_elements>, <max_elements>]
+* ["tuple", [ <list_of_dtypes ]]
+* ["struct", { <name_of_component_as_json_string>:<dtype>}]
+
+Examples
+++++++++
+
+* status: ["tuple", [ ["enum", {0:"init", 100:"idle", 200:"warn", 300:"busy"}], ["string", 255] ] ]
+* p/pi/pid-triple: ["array", ["double", 0, 100], 1, 3]
+
+
+Meeting 30.5.2017
+-----------------
+
+* data values can be transferred as json_null, meaning: no value yet
+* json_null can not be used inside structured data types
+* property name for datatype is "datatype"
+
+Meeting 11.9.2017
+-----------------
+
+Merge datatype and validator
+++++++++++++++++++++++++++++
+
+  * enum, int, double, bool, tuple, struct as before
+  * ["blob", <maximum_size_in_bytes>] or ["blob", <maximum_size_in_bytes>, <minimum_size_in_bytes>]
+  * ["string", <maximum_allowed_length>] or ["string", <max_size_in_bytes>, <minimum_size_in_bytes>]
+  * ["array", <basic_data_type>, <max_elements>] or ["array", <dtype>, <max_elements>, <min_elements>]
+
+Interface_class
++++++++++++++++
+
+  * Drivable, Writable, Readable, Module (first character uppercase, no middle 'e')
+