Add build option V7_NO_COMPILER

Which disables tokenizer, parser, AST, and compiler. On ESP8266, it
frees 21K of ROM.

PUBLISHED_FROM=ff4c53ace6b9056c595b9e12ef3453330d659775

docs/design-concept/events.md

@@ -2,36 +2,36 @@
 title: Events
 ---
 
-Mongoose accepts incoming connections, reads and writes data, and calls
-specified event handler for each connection when appropriate. Typical event
+Mongoose accepts incoming connections, reads and writes data and calls
+specified event handlers for each connection when appropriate. A typical event
 sequence is this:
 
-- For outbound connection: `MG_EV_CONNECT` -> (`MG_EV_RECV`, `MG_EV_SEND`,
+- For an outbound connection: `MG_EV_CONNECT` -> (`MG_EV_RECV`, `MG_EV_SEND`,
   `MG_EV_POLL` ...) -> `MG_EV_CLOSE`
-- For inbound connection: `MG_EV_ACCEPT` ->  (`MG_EV_RECV`, `MG_EV_SEND`,
+- For an inbound connection: `MG_EV_ACCEPT` ->  (`MG_EV_RECV`, `MG_EV_SEND`,
   `MG_EV_POLL` ...) -> `MG_EV_CLOSE`
 
 
 Below is a list of core events triggered by Mongoose (note that each protocol
 triggers protocol-specific events in addition to the core ones):
 
-- `MG_EV_ACCEPT`: sent when new server connection is accepted by a listening
+- `MG_EV_ACCEPT`: sent when a new server connection is accepted by a listening
   connection. `void *ev_data` is `union socket_address` of the remote peer.
 
 - `MG_EV_CONNECT`: sent when a new outbound connection created by `mg_connect()`
   either failed or succeeded. `void *ev_data` is `int *success`.  If `success`
-  is 0, then connection has been established, otherwise it contains error code.
+  is 0, then the connection has been established, otherwise it contains an error code.
   See `mg_connect_opt()` function for code example.
 
 - `MG_EV_RECV`: New data is received and appended to the end of `recv_mbuf`.
   `void *ev_data` is `int *num_received_bytes`. Typically, event handler should
   check received data in `nc->recv_mbuf`, discard processed data by calling
   `mbuf_remove()`, set connection flags `nc->flags` if necessary (see `struct
-  mg_connection`), and write data the remote peer by output functions like
+  mg_connection`) and write data the remote peer by output functions like
   `mg_send()`.
 
-  **WARNING**: Mongoose uses `realloc()` to expand receive buffer.  It is
-  user's responsibility to discard processed data from the beginning of receive
+  **WARNING**: Mongoose uses `realloc()` to expand the receive buffer. It is
+  the user's responsibility to discard processed data from the beginning of the receive
   buffer, note the `mbuf_remove()` call in the example above.
 
 - `MG_EV_SEND`: Mongoose has written data to the remote peer and discarded
@@ -39,14 +39,14 @@ triggers protocol-specific events in addition to the core ones):
   *num_sent_bytes`.
 
   **NOTE**: Mongoose output functions only append data to the
-  `mg_connection::send_mbuf`, they do not do any socket writes.  An actual IO
-  is done by `mg_mgr_poll()`. `MG_EV_SEND` event is just a notification about
+  `mg_connection::send_mbuf`. They do not do any socket writes. An actual IO
+  is done by `mg_mgr_poll()`. An `MG_EV_SEND` event is just a notification about
   an IO has been done.
 
 - `MG_EV_POLL`: Sent to all connections on each invocation of `mg_mgr_poll()`.
-  This event could be used to do any housekeeping, for example check whether
-  certain timeout has expired and close the connection, or send heartbeet
-  message, et cetera.
+  This event could be used to do any housekeeping, for example check whether a
+  certain timeout has expired and closes the connection or send heartbeat
+  message, etc.
 
 - `MG_EV_TIMER`: Sent to the connection if `mg_set_timer()` was called.