Implement a Dafny server.

The Dafny server is a command line utility that allows non-.Net editors to take
advantage of Dafny's caching facilities, as used by the Dafny extension for
Visual Studio. The server is essentially a REPL, which produces output in the
same format as the Dafny CLI; clients thus do not need to understand the
internals of Dafny's caching. A typical editing session proceeds as follows:

* When a new Dafny file is opened, the editor starts a new instance of the
  Dafny server. The cache is blank at that point.
* The editor sends a copy of the buffer for initial verification. This takes
  some time, after which the server returns a list of errors.
* The user makes modifications; the editor periodically sends a new copy of
  the buffer's contents to the Dafny server, which quickly returns an updated
  list of errors.

The client-server protocol is sequential, uses JSON, and works over ASCII
pipes by base64-encoding queries. It defines one type of query, and two types
of responses:

Queries are of the following form:
   verify
   <base64 encoded JSON payload>
   [[DAFNY-CLIENT: EOM]]

Responses are of the following form:
   <list of errors and usual output, as produced by the Dafny CLI>
   [SUCCESS] [[DAFNY-SERVER: EOM]]
or
   <error message>
   [FAILURE] [[DAFNY-SERVER: EOM]]

The JSON payload is an array with 4 fields:
   * args:   An array of Dafny arguments, as passed to the Dafny CLI
   * source: A Dafny program, or the path to a Dafny source file.
   * sourceIsFile: A boolean indicating whether the 'source' argument is a
                   Dafny program or the path to one.
   * filename:     The name of the original source file, to be used in error
                   messages

For small files, embedding the Dafny source directly into a message is
convenient; for larger files, however, it is generally better for performance
to write the source snapshot to a separate file, and to pass that to Dafny
by setting the 'sourceIsFile' flag to true.

1 files changed, 6 insertions, 0 deletions

diff --git a/Source/DafnyServer/App.config b/Source/DafnyServer/App.config
new file mode 100644
index 00000000..fad249e4
--- /dev/null
+++ b/Source/DafnyServer/App.config
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>

+<configuration>

+    <startup> 

+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />

+    </startup>

+</configuration>
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