first steps for cleaner static/const distinction

doc/advopt.txt

@@ -51,6 +51,7 @@ Advanced options:
   --tlsEmulation:on|off     turn thread local storage emulation on|off
   --taintMode:on|off        turn taint mode on|off
   --symbolFiles:on|off      turn symbol files on|off (experimental)
+  --implicitStatic:on|off   turn implicit compile time evaluation on|off
   --skipCfg                 do not read the general configuration file
   --skipUserCfg             do not read the user's configuration file
   --skipParentCfg           do not read the parent dirs' configuration files

doc/grammar.txt

@@ -26,6 +26,7 @@ indexExpr ::= expr
 
 castExpr ::= 'cast' '[' optInd typeDesc optPar ']' '(' optInd expr optPar ')'
 addrExpr ::= 'addr' '(' optInd expr optPar ')'
+staticExpr ::= 'static' '(' optInd expr optPar ')'
 symbol ::= '`' (KEYWORD | IDENT | operator | '(' ')' | '[' ']' | '{' '}'
                | '=' | literal)+ '`'
          | IDENT
@@ -37,7 +38,7 @@ primarySuffix ::= '.' optInd symbol [generalizedLit]
                 | '{' optInd [indexExpr (comma indexExpr)* [comma]] optPar '}'
 
 primary ::= primaryPrefix* (symbol [generalizedLit] | 
-                            constructor | castExpr | addrExpr)
+                            constructor | castExpr | addrExpr | staticExpr)
             primarySuffix*
 
 generalizedLit ::= GENERALIZED_STR_LIT | GENERALIZED_TRIPLESTR_LIT
@@ -97,7 +98,7 @@ simpleStmt ::= returnStmt
              | includeStmt
              | exprStmt
 complexStmt ::= ifStmt | whileStmt | caseStmt | tryStmt | forStmt
-              | blockStmt | asmStmt
+              | blockStmt | staticStmt | asmStmt
               | procDecl | iteratorDecl | macroDecl | templateDecl | methodDecl
               | constSection | letSection | varSection
               | typeSection | whenStmt | bindStmt
@@ -131,6 +132,7 @@ tryStmt ::= 'try' ':' stmt
            ['finally' ':' stmt]
 asmStmt ::= 'asm' [pragma] (STR_LIT | RSTR_LIT | TRIPLESTR_LIT)
 blockStmt ::= 'block' [symbol] ':' stmt
+staticStmt ::= 'static' ':' stmt
 filename ::= symbol | STR_LIT | RSTR_LIT | TRIPLESTR_LIT
 importStmt ::= 'import' filename (comma filename)*
 includeStmt ::= 'include' filename (comma filename)*

doc/keywords.txt

@@ -12,7 +12,7 @@ nil not notin
 object of or out
 proc ptr
 raise ref return
-shl shr
+shl shr static
 template try tuple type
 var
 when while with without

doc/manual.txt

@@ -1640,6 +1640,30 @@ Constants cannot be of type ``ptr``, ``ref``, ``var`` or ``object``, nor can
 they contain such a type.
 
 
+Static statement/expression
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Syntax::
+  staticExpr ::= 'static' '(' optInd expr optPar ')'
+  staticStmt ::= 'static' ':' stmt
+  
+A `static`:idx: statement/expression can be used to enforce compile 
+time evaluation explicitely. Enforced compile time evaluation can even evaluate
+code that has side effects: 
+
+.. code-block::
+
+  static:
+    echo "echo at compile time"
+
+It's a static error if the compiler cannot perform the evaluation at compile time.
+
+The current implementation poses some restrictions for compile time
+evaluation: Code which contains ``cast`` or makes use of the foreign function
+interface cannot be evaluated at compile time. Later versions of Nimrod will
+support the FFI at compile time.
+
+
 If statement
 ~~~~~~~~~~~~