@@ -343,6 +343,7 @@ -a, --asset-path          Specify a directory containing the asset files to include in the
                               compiled executable (if -c is set)
     -c, --compile             Compile the specified file
     -e, --evaluate            Evaluate a $exe program inline
+    -s, --safe                Enable runtime checks
     -h, --help                Print this help$iOpt
     -j, --interactive-simple  Start $exe shell (without advanced prompt)
     -l, --log                 Set log level (debug|info|notice|warn|error|fatal)
@@ -378,6 +379,8 @@ of "asset-path", "a":
             ASSETPATH = val
           of "prelude", "p":
             customPrelude = val
+          of "runtime-checks", "r":
+            SAFE = true
           of "log", "l":
             if file == "":
               var val = val

@@ -18,3 +18,6 @@ var EDITOR* {.threadvar.}: LineEditor
 EDITOR = initEditor(historyFile = MINHISTORY)
 var MINCOMPILED* {.threadvar.}: bool
 MINCOMPILED = false
+var SAFE* {.threadvar.}: bool
+SAFE = false
+

@@ -7,6 +7,7 @@ parser,
   value,
   json,
   scope,
+  env,
   interpreter
   
 # Library methods
@@ -291,6 +292,12 @@ 
 
 # The following is used in operator signatures
 proc expect*(i: var MinInterpreter, elements: varargs[string], generics: var CritBitTree[string]): seq[MinValue] {.gcsafe.}=
+  if not SAFE:
+    # Ignore validation, just return elements
+    result = newSeq[MinValue](0)
+    for el in elements:
+      result.add i.pop
+    return result
   let sym = i.currSym.getString
   var valid = newSeq[string](0)
   result = newSeq[MinValue](0)

@@ -1,1 +1,3 @@ 
+### BREAKING CHANGES
 
+* Runtime checks (expectations) must now be manually activated by specifying `-s` or `--safe`.

@@ -109,6 +109,10 @@ > %min-terminal%
 > 
 > [$](class:prompt) cat myfile.min | min
 
+> %tip%
+> 
+> You can enable runtime checks and validations by spacifying `-s` or `--safe` when running a min program.
+
 ## Compiling a min Program
 
 min programs can be compiled to a single executable simply by specifying the `-c` (or `--compile`) flag when executing a min file:

@@ -115,7 +115,7 @@ {#op||exit||{{i}}||{{none}}||
 Exits the program or shell with {{i}} as return code. #}
 
 {#op||expect||{{q1}}||{{q2}}||
-> Validates the first _n_ elements of the stack against the type descriptions specified in {{q1}} (_n_ is {{q1}}'s length) and if all the elements are valid returns them wrapped in {{q2}} (in reverse order). 
+> If the `-s` or `--safe` is specified when running the program, validates the first _n_ elements of the stack against the type descriptions specified in {{q1}} (_n_ is {{q1}}'s length) and if all the elements are valid returns them wrapped in {{q2}} (in reverse order). If the neither `-s` nor `--safe` is specified when running the program, no validation is performed and all elements are just returned in a quotation in reverse order. 
 
 > > %tip%
 > > Tips
@@ -286,7 +286,7 @@ > * A quotation identifying the body of the operator.
 >
 > The main additional features offered by this way of defining operators are the following:
 >
-> * Both input and output values are checked against a type (like when using the `expect` operator *and* automatically captured in a symbol that can be referenced in the operator body quotation.
+> * (if the `-s` or `--safe` is specified when running the program) Both input and output values are checked against a type (like when using the `expect` operator *and* automatically captured in a symbol that can be referenced in the operator body quotation.
 > * The full signature of the operator is declared, making the resulting code easier to understand at quick glance.
 > * An exception is automatically raised if the operator body pollutes the stack by adding or removing elementa from the stack (besides adding the declared output values).
 > * It is possible to use the `return` symbol within the body quotation to immediately stop the evaluation of the body quotation and automatically push the output values on the stack.