doc: Adding getting started

README.md

@@ -1,18 +1,75 @@
 ECAL
 ====
-ECAL is an ECA (Event Condition Action) language for concurrent event processing. ECAL can define event-based systems using rules which are triggered by events.
+ECAL is an ECA (Event Condition Action) language for concurrent event processing. ECAL can define event-based systems using rules which are triggered by events. ECAL is intended to be embedded into other software to provide an easy to use scripting language which can react to external events.
 
 Features
 --------
-- Simple but powerful concurrent event-based processing.
-- Priorities for control flow.
-- Event cascades can be traced with monitors.
-- Rules which can match on event state.
-- Rules can suppress each other.
+- Simple intuitive syntax
+- Minimalistic base language
+- Language can be easily extended either by auto generating bridge adapters to Go functions or by adding custom function into the stdlib
+- External events can be easily pushed into the interpreter and scripts written in ECAL can react to the events.
+- Simple but powerful concurrent event-based processing supporting priorities and scoping for control flow.
+- Handling event rules can match on event state and rules can suppress each other.
+
+### Getting started
+
+Clone the repository and build the ECAL executable with a simple `make` command. You need Go 1.14 or higher.
+
+Run `./ecal` to start an interactive session. You can now write simple one line statements and evaluate them:
+
+```
+>>>a:=2;b:=a*4;a+b
+10
+>>>"Result is {{a+b}}"
+Result is 10
+```
+
+Close the interpreter by pressing <ctrl>+d and change into the directory `examples/fib`.
+There are 2 ECAL files in here:
+
+lib.ecal
+```
+# Library for fib
+
+/*
+fib calculates the fibonacci series using recursion.
+*/
+func fib(n) {
+    if (n <= 1) {
+        return n
+    }
+    return fib(n-1) + fib(n-2)
+}
+```
+
+fib.ecal
+```
+import "lib.ecal" as lib
+
+for a in range(2, 20, 2) {
+  log("fib({{a}}) = ", lib.fib(a))
+}
+```
+
+Run the ECAL program with: `sh run.sh`. The output should be like:
+```
+$ sh run.sh
+2000/01/01 12:12:01 fib(2) = 1
+2000/01/01 12:12:01 fib(4) = 3
+2000/01/01 12:12:01 fib(6) = 8
+2000/01/01 12:12:01 fib(8) = 21
+2000/01/01 12:12:01 fib(10) = 55
+2000/01/01 12:12:01 fib(12) = 144
+2000/01/01 12:12:02 fib(14) = 377
+2000/01/01 12:12:02 fib(16) = 987
+2000/01/01 12:12:02 fib(18) = 2584
+2000/01/01 12:12:02 fib(20) = 6765
+```
 
 ### Further Reading:
 
 - [ECA Language](ecal.md)
+- [ECA Engine](engine.md)
 
 License
 -------

cli/ecal.go

@@ -21,9 +21,6 @@ import (
 
 /*
 TODO:
-- cron trigger (async) in-build function
-- web server (sync/async) in-build function with options
-- web request library
 - create executable binary (pack into single binary)
 - debug server support (vscode)
 */

examples/fib/fib.ecal

@@ -1,3 +1,5 @@
 import "lib.ecal" as lib
 
-log("fib(1) = ", lib.fib(12))
+for a in range(2, 20, 2) {
+  log("fib({{a}}) = ", lib.fib(a))
+}