misc tuning, following hint by IntelliJ;

clarified signature;

more robust: avoid potentially unrelated snapshot for the sake of is_suppressed;

clarified Node_Status vs. is_suppressed, e.g. relevant for purged nodes in Theories_Dockable after 0626cae56b6f;

clarified protocol;

clarified signature;

tuned signature;

clarified signature, e.g. for re-use by other servers;

clarified modules and signature;

more uniform multi-language operations;
clarified modules and signature;

more uniform multi-language operations;

static type for Library.using: avoid Java 11 warnings on "Illegal reflective access";
more uses of "using";

proper return code for runtime failure;

clarified modules;

--HG--
rename : src/Pure/Thy/thy_resources.scala => src/Pure/PIDE/headless.scala

clarified theory progress;

clarified signature;

tuned signature;

clarified Nodes_Status;
tuned messages;

optional notification of nodes_status (via progress);
more accurate changed.nodes wrt. dep_theories;
tuned signature;

remove trailing commas

clarified signature: more uniform theory_message (see also d7920eb7de54);

added command "purge_theories";
proper documentation: command "use_theories" is asynchronous;

field "kind" is always present, with default "writeln";

clarified signature;

proper order of matches: Server.Error is an instance of Exn.ERROR;

clarified markup according to common Command.Results;

documentation for the Isabelle server;

clarified message name: disallow single quote;

clarified server shutdown: stop all sessions;

more explicit error messages;
clarified signature;

clarified exception handling: include interrupts;

tuned signature;

prefer typed UUID;

unload_theories after consolidation -- reset node_required;
proper node_perspective (amending 0d8e4e777973);

support for "use_theories";

clarified signature;

proper options;

tuned options;

tuned message -- more readable JSON;

store session: per Server/Context, not Connection;
support for "session_stop";

clarified server log;
tuned options;

support for "session_start";

clarified message;

asynchronous "session_build";

support for asynchronous tasks, with "cancel" command;

tuned signature;

more informative error with JSON result;
tuned signature;

tuned signature;

added server command "session_build": similar to JEdit_Resources.session_build;

tuned signature;
tuned output;

explicit Server.Context with output channels (concurrent write);
support for Logger and Progress;

allow "." in message name;

re-use existing in/out streams;

tuned;

tuned signature;

clarified signature -- do not expose socket;

more options;

clarified default server name;

more uniform output: this may be parsed by another program;

clarified argument formats: explicit Unit, allow XML.Elem as well;
tuned messages: prefer single quotes for JSON output;

tuned output;

more options: client without implicit server startup;

more flexible message formats;

clarified signature;

option for console interaction;

more uniform Bytes.read_line/read_block operations;

added Reply.NOTE for asynchronous notifications;

more operations;

more thorough init: purge inactive entries;

more generous timeout;

Entry.connection: proview password here;
more robust checks;

clarified initial protocol;

ignore empty lines;

tuned;

more robust read_line after shutdown;

more implicit wire protocol;

tuned signature;

clarified server start, notably for invocation within regular Isabelle/Scala process;

tuned signature;

tuned signature;

clarified toString operations;

clarified socket connection;

server commands may access Server;
Server.stop: proper shutdown;
clarified signature;

tuned -- avoid regex matching on potentially large string;
clarified message: command name could be malformed;

avoid println with its extra CR on Windows;

some concrete commands;
clarified messages;

more formal messages;

clarified command language;

tuned signature;

proper check for active server;

clarified signature;

tuned signature;

handle server connections;

clarified database names;

more options;
misc tuning and clarification;

support for resident Isabelle servers;