change let to val

Author: dr-orlovsky

content/design.md

@@ -85,11 +85,11 @@ Some examples of specifiers are:
   which is `x U64, y U65`. Data type specifiers contain no body.
 - value specifier:
   ```
-  let value: U8 := 5
+  val value: U8 := 5
   ```
-  where `let value` is a *value declaration*, separated with colon from the type information, which is `U8`. Next,
+  where `val value` is a *value declaration*, separated with colon from the type information, which is `U8`. Next,
   the body contains the value assigned to the named value instance. Value specifications may have data type omitted in
-  situations when it can be inferred; for instance, we can also write the specifier above as `let value := 5#U8`, where
+  situations when it can be inferred; for instance, we can also write the specifier above as `val value := 5#U8`, where
   `#U8` is a type annotation.
 
 <div></div>
@@ -165,7 +165,7 @@ following manner:
 ```
 fx twoArgsFn: x U32, y U32 -> U32
 
-let coord := x U32, y U32
+val coord := x U32, y U32
 twoArgsFn coord 
 ```
 
@@ -196,7 +196,7 @@ with `|:`:
 ```
 data WorldDirection: north | south | west | east
 
-let sample: WorldDirection
+val sample: WorldDirection
 
 sample >|                   – match sample {
   north |? doSomething1     –   north => {} 
@@ -501,7 +501,7 @@ type may be omitted, and in this case if is inferred by the compiler from the bo
 
 Finally, there is the multiline forms of lambda expressions:
 ```
-let lambdaFn := .\
+lambda lambdaFn
     statement1
     statement2
 ```
@@ -523,7 +523,7 @@ someFn arg1, .\(x U8 -> U16
 
 The type of the lambda expression is `.\ input -> output`, and this type may be used in type annotations:
 ```
-let squared: .\U8 -> U16 := .\pow 2
+val squared: .\U8 -> U16 := .\pow 2
 ```
 
 <!-- TODO: add on currying:

content/examples.md

@@ -58,8 +58,8 @@ data Result: T any, E error => ok(T) | err(E)
 
 ```
 infx `+`: a Coord2D, b Coord2D -> Coord2D
-  let x := a.x + b.x
-  let y := a.y + b.y
+  val x := a.x + b.x
+  val y := a.y + b.y
   x, y
 ```
 
@@ -68,7 +68,7 @@ infx `+`: a Coord2D, b Coord2D -> Coord2D
 ```
 data WorldDirection: north | south | west | east
 
-let sample: WorldDirection = random
+val sample: WorldDirection = random
 
 sample >|
   north |? println("I am northman") 
@@ -101,7 +101,7 @@ infx findFirst: V eq, I iter(item eq) => iter I, value V -> U64?
     enumerate iter |> fst =? value |? $ := lst _
 
 infx hasUnique: V eq, I iter(item eq) => iter I, value V -> Bool
-    let index := iter findFirst value !! false
+    val index := iter findFirst value !! false
     (iter[index..] |> =? value |? $ := false) ?? true
     
 [0, 1, 2, 3, 4] hasUnique 1 -- true
@@ -110,7 +110,7 @@ infx hasUnique: V eq, I iter(item eq) => iter I, value V -> Bool
 ### Collection comprehensions
 
 ```
-let congratulations :=
+val congratulations :=
     [ "Happy birthday, \(_)" <| birthdays.values.flatten ]
 ```
 
@@ -120,8 +120,8 @@ let congratulations :=
   fx sumOrZero: x U32, y U32 -> U32
     x +? y ?? 0 -- here we return zero on overflow
 
-  let x, y: U32, U32 := random, random
-  let sum = x +? y !! overflow -- here we return Err(overflow) on overflow
+  val x, y: U32, U32 := random, random
+  val sum = x +? y !! overflow -- here we return Err(overflow) on overflow
   sumOrZero sum, x
 ```
 

content/reference.md

@@ -489,14 +489,14 @@ iterations, like with `$-1`, accessing the previous iteration result, or
 definition and body:
 
 ```
-let local: U8 = random
+val local: U8 = random
 lambda sq: x U8 -> U32
     pow 2 + local
 ```
 
 As any other specifier it can be put into a single line:
 ```
-let local: U8 = random
+val local: U8 = random
 lambda sq: x U8 -> U32 := pow 2 + local
 ```