[papgets] add exponentiation operator to papgets

conf/gcs/papgets.xml

@@ -54,6 +54,13 @@
         <property name="color" value="white"/>
       </papget>
 
+      <papget type="expression" display="text" x="600" y="422">
+        <property name="expr" value="NAVIGATION.dist2_home ** 0.5"/>
+        <property name="size" value="15."/>
+        <property name="format" value="HOME dist: %.1fm"/>
+        <property name="color" value="white"/>
+      </papget>
+
       <papget type="variable_setting" display="button" x="10" y="250">
         <property name="variable" value="launch"/>
         <property name="value" value="1."/>

sw/lib/ocaml/expr_lexer.mll

@@ -50,6 +50,7 @@ rule token = parse
   | "+" { PLUS }
   | "=" { ASSIGN }
   | "-" { MINUS }
+  | "**" { EXPO }
   | "*" { MULT }
   | "/" { DIV }
   | "!" { NOT }

sw/lib/ocaml/expr_parser.mly

@@ -30,12 +30,12 @@ open Expr_syntax
 %token DOT COMMA SEMICOLON LP RP LC RC LB RB DEREF AND COLON OR
 %token EQ GT ASSIGN GEQ NOT
 %token PLUS MINUS
-%token MULT DIV MOD
+%token MULT DIV MOD EXPO
 
 %left AND OR	/* lowest precedence */
 %left EQ GT ASSIGN GEQ
 %left PLUS MINUS
-%left MULT DIV MOD
+%left MULT DIV MOD EXPO
 %nonassoc NOT
 %nonassoc UMINUS
 %left DEREF /* highest precedence */
@@ -56,6 +56,7 @@ expression:
   | expression MULT expression { CallOperator ("*",[$1;$3]) }
   | expression DIV expression { CallOperator ("/",[$1;$3]) }
   | expression MOD expression { CallOperator ("%",[$1;$3]) }
+  | expression EXPO expression { CallOperator ("**",[$1;$3]) }
   | MINUS expression %prec UMINUS { CallOperator ("-",[$2]) }
   | NOT expression { CallOperator ("!",[$2]) }
   | INT { Int $1 }

sw/lib/ocaml/papget.ml

@@ -102,10 +102,11 @@ let hash_vars = fun expr ->
 let wrap = fun f ->
   fun x y -> string_of_float (f (float_of_string x) (float_of_string y))
 let eval_bin_op = function
-"*" -> wrap ( *. )
+  | "*" -> wrap ( *. )
   | "+" -> wrap ( +. )
   | "-" -> wrap ( -. )
   | "/" -> wrap ( /. )
+  | "**" -> wrap ( ** )
   | op -> failwith (sprintf "Papget.eval_expr '%s'" op)
 
 let eval_expr = fun (extra_functions:(string * (string list -> string)) list) h e ->