upd readme - more examples

docs/readme.md

@@ -107,10 +107,15 @@ my_func(X) -> X * 4.
 ->
 ```dlang
 int my_func(int x) {
-    if (x == 1) return 1;
-    else if (x == 5) return x * 2;
-    else if (x == 9) return x * 3;
-    else return x * 4; // other cases
+    if (x == 1){
+        return 1;
+    }else if (x == 5){
+        return x * 2;
+    }else if (x == 9){
+        return x * 3;
+    }else{ // other cases
+        return x * 4;
+    }
 }
 
 // or
@@ -130,8 +135,102 @@ int my_func(int x) {
 ```
 note that compiler can optimise few comparison conditions for ```switch``` better than that in ```if .. else```.  
 
-todo add examples
 
+### 2.4.1 pattern matching examples
+```
+// left = function type, right = arguments type
+int = int x
+my_func 1 = 1
+my_func 5 = 5 * 2
+my_func 9 = 9 * 3
+my_func X = X * 4
+
+->
+
+int my_func(int x) {
+    if (x == 1){
+        return 1;
+    }else if (x == 5){
+        return 5 * 2; // return x * 2;
+    }else if (x == 9){
+        return 9 * 3; // return x * 3;
+    }else{ // other cases
+        return x * 4;
+    }
+}
+```
+
+```
+// left = function type, right = arguments type
+// sw = use switch
+int sw = int x
+my_func 1 = 1
+my_func 5 = 5 * 2
+my_func 9 = 9 * 3
+my_func X = X * 4
+
+->
+
+int my_func(int x) {
+    switch (x) {
+        case 1:
+            return 1; // if x == 1
+        case 5:
+            return 5 * 2; // return x * 2; // if x == 5
+        case 9:
+            return 9 * 3; // return x * 3; // if x == 9
+        default:
+            return x * 4; // other cases
+    }
+}
+```
+
+```
+y = case x
+  1 = 1
+  5 = 5 * 2
+  9 = 9 * 3
+  _ = x * 4
+
+->
+
+if (x == 1){
+    y = 1;
+}else if (x == 5){
+    y = 5 * 2; // return x * 2;
+}else if (x == 9){
+    y = 9 * 3; // return x * 3;
+}else{ // other cases
+    y = x * 4;
+}
+```
+
+```
+// sw case = use switch in dlang for this case
+y = sw case x
+  1 = 1
+  5 = 5 * 2
+  9 = 9 * 3
+  _ = x * 4
+
+->
+
+switch (x) {
+    case 1:
+        y = 1; // if x == 1
+    case 5:
+        y = 5 * 2; // y = x * 2; // if x == 5
+    case 9:
+        y = 9 * 3; // y = x * 3; // if x == 9
+    default:
+        y = x * 4; // other cases
+}
+```
+
+todo more examples -- with switch case dlang
+```
+
+```
 
 ## 2.5 aliases for imports, externs etc
 ```
@@ -146,10 +245,72 @@ import std.array;
 import std.string;
 import std.algorithm;
 ```
+
+```
+use core.stdc.stdio [ printf scanf ]
+    std.conv [ to ]
+
+->
+import core.stdc.stdio : printf, scanf;
+import std.conv : to;
+```
+
+```
+use as use_std1
+    core.stdc.stdio [ printf scanf ]
+    std.conv [ to ]
+
+
+use_std1 // use elsewhere in the file
+
+->
+import core.stdc.stdio : printf, scanf;
+import std.conv : to;
+```
 todo add more examples
 
 
-## 2.6 code between ```dlang``` reserved words translates into target .d file without changes
+## 2.6 main, wasm import from js (wasm export to js = as usual function + return)
+```
+main
+
+->
+
+void main()
+{
+...
+```
+
+```
+smain
+
+->
+
+extern(C) void main()
+{
+...
+```
+
+```
+// for wasm
+wmain
+
+->
+
+void _start(){  }
+```
+
+```
+// wasm import from js
+wuse print int a
+
+->
+
+void print(int a);
+```
+
+
+## 2.7 code between ```dlang``` reserved words translates into target .d file without changes
 ```
 ...
 
@@ -163,7 +324,7 @@ dlang
 ```
 
 
-## 2.7 reserved words (keywords) list
+## 2.8 reserved words (keywords) list
 including https://dlang.org/spec/lex.html#keywords  
 ```
 abstract alias align asm assert auto