ocean: introduce prefix op for string->number conversion.

Rather than having magic conversion of command line args to numbers as
needed, introduce '$' as a prefix op to to the conversion.
This is a step towards changing 'program' to be a 'main' function.

Signed-off-by: NeilBrown <neil@brown.name>

diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc
index e3739ed940802dd324eebc14fec1eefdc03c8be4..5e911925fd39d5a80c3eec0edc0c37614a486666 100644 (file)
--- a/csrc/oceani-tests.mdc
+++ b/csrc/oceani-tests.mdc
@@ -282,7 +282,8 @@ Here I break it into two parts, keeping the array code separate.
 
 ###### test: sayhello
 
-       program A B astr bbool:
+       program As Bs astr bbool:
+               A := $As; B := $Bs
                print "Hello World, what lovely oceans you have!"
                /* When a variable is defined in both branches of an 'if',
                 * and used afterwards, the variables are merged.

diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index 520212be6d144365a586638bf695098689460058..d690b70fb5c795ee481483db747f794f28850381 100644 (file)
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -2772,9 +2772,14 @@ expression operator, and the `CMPop` non-terminal will match one of them.
 
 ### Expressions: The rest
 
-The remaining expressions with the highest precedence are arithmetic and
-string concatenation.  String concatenation (`++`) has the same
-precedence as multiplication and division, but lower than the uniary.
+The remaining expressions with the highest precedence are arithmetic,
+string concatenation, and string conversion.  String concatenation
+(`++`) has the same precedence as multiplication and division, but lower
+than the uniary.
+
+String conversion is a temporary feature until I get a better type
+system.  `$` is a prefix operator which expects a string and returns
+a number.
 
 `+` and `-` are both infix and prefix operations (where they are
 absolute value and negation).  These have different operator names.
@@ -2788,12 +2793,13 @@ should only insert brackets were needed for precedence.
        Times, Divide, Rem,
        Concat,
        Absolute, Negate,
+       StringConv,
        Bracket,
 
 ###### expr precedence
        $LEFT + - Eop
        $LEFT * / % ++ Top
-       $LEFT Uop
+       $LEFT Uop $
        $TERM ( )
 
 ###### expression grammar
@@ -2834,6 +2840,7 @@ should only insert brackets were needed for precedence.
 
        Uop ->    + ${ $0.op = Absolute; }$
                | - ${ $0.op = Negate; }$
+               | $ ${ $0.op = StringConv; }$
 
        Top ->    * ${ $0.op = Times; }$
                | / ${ $0.op = Divide; }$
@@ -2862,14 +2869,15 @@ should only insert brackets were needed for precedence.
                if (bracket) printf(")");
                break;
        case Absolute:
-               if (bracket) printf("(");
-               printf("+");
-               print_exec(b->right, indent, bracket);
-               if (bracket) printf(")");
-               break;
        case Negate:
+       case StringConv:
                if (bracket) printf("(");
-               printf("-");
+               switch (b->op) {
+               case Absolute:   fputs("+", stdout); break;
+               case Negate:     fputs("-", stdout); break;
+               case StringConv: fputs("$", stdout); break;
+               default: abort();       // NOTEST
+               }                       // NOTEST
                print_exec(b->right, indent, bracket);
                if (bracket) printf(")");
                break;
@@ -2906,6 +2914,15 @@ should only insert brackets were needed for precedence.
                                   Tstr, rules, type);
                return Tstr;
 
+       case StringConv:
+               /* op must be string, result is number */
+               propagate_types(b->left, c, ok, Tstr, 0);
+               if (!type_compat(type, Tnum, 0))
+                       type_err(c,
+                         "error: Can only convert string to number, not %1",
+                               prog, type, 0, NULL);
+               return Tnum;
+
        case Bracket:
                return propagate_types(b->right, c, ok, type, 0);
 
@@ -2963,6 +2980,14 @@ should only insert brackets were needed for precedence.
                rvtype = Tstr;
                rv.str = text_join(left.str, right.str);
                break;
+       case StringConv:
+               right = interp_exec(b->right, &rvtype);
+               rtype = Tstr;
+               rvtype = Tnum;
+               char *str = strndup(right.str.txt, right.str.len);
+               parse_value(rvtype, str, &rv);
+               free(str);
+               break;
 
 ###### value functions
 
@@ -4248,11 +4273,13 @@ things which will likely grow as the languages grows.
                name:string
                alive:Boolean
 
-       program A B:
+       program Astr Bstr:
                print "Hello World, what lovely oceans you have!"
                print "Are there", five, "?"
                print pi, pie, "but", cake
 
+               A := $Astr; B := $Bstr
+
                /* When a variable is defined in both branches of an 'if',
                 * and used afterwards, the variables are merged.
                 */