Const arrays

docs/abi/undefined-behaviour.md

@@ -10,6 +10,8 @@ even up to hardware damage.
 
 * array overruns: indexing past the end of an array leads to undefined behaviour 
 
+* writing to arrays defined as `const`
+
 * stray pointers: indexing a pointer that doesn't point to a valid object or indexing it past the end of the pointed object leads to undefined behaviour
 
 * reading uninitialized variables: will return undefined values

docs/lang/literals.md

@@ -21,6 +21,8 @@ It is not allowed in any other places.
 
 String literals can be used as either array initializers or expressions of type `pointer`.
 
+String literals are equivalent to constanr arrays. Writing to them via their pointer is undefined behaviour.
+
 If a string literal is used as an expression, then the text data will be located in the default code segment,
 regardless of which code segment the current function is located it. This may be subject to change in future releases.
 

docs/lang/syntax.md

@@ -106,12 +106,14 @@ An array is a continuous sequence of bytes in memory.
 
 Syntax:
 
-`[segment(<segment>)] array [(<element type>)] <name> [[<size>]] [align ( <alignment> )] [@<address>] [= <initial_values>]`
+`[segment(<segment>)] [const] array [(<element type>)] <name> [[<size>]] [align ( <alignment> )] [@<address>] [= <initial_values>]`
 
 * `<segment>`: segment name; if absent,
 then defaults to `default_code_segment` as defined for the platform if the array has initial values,
 or to `default` if it doesn't.
 
+* if `const` is present, the array is read-only. Read-only arrays have to have a fixed address and/or defined contents.
+
 * `<element type>`: type of the elements of the array.
 It must be of size 1 byte.
 If omitted, the default is `byte`.