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'TO' expected

Velox reports 'TO' expected after it has parsed the counter and initial value of a for statement but cannot find either direction keyword. Despite the message naming only TO, the compiler accepts both to and downto.

Syntax​

for Counter := InitialValue to FinalValue do
  Statement;

for Counter := InitialValue downto FinalValue do
  Statement;

Example​

This loop omits its direction:

procedure ScriptEvent(var Value: Variant);
var
  I: Integer;
begin
  for I := 1 3 do // Error: 'TO' expected
    Value := I;
end;

Add to for an ascending loop or downto for a descending loop:

procedure ScriptEvent(var Value: Variant);
var
  I: Integer;
begin
  for I := 1 to 3 do
    Value := I;
end;

How Velox detects it​

The for compiler performs these steps in order:

  1. Resolve the counter as writable variable storage.
  2. Require := and parse the initial-value expression.
  3. Test the next token for to or downto.
  4. Emit ecToExpected if neither token is present.
  5. Parse the final-value expression and then require do.

The diagnostic therefore points at the token after the initial value. A malformed initial expression can move that detection point or produce a more specific expression error first.

Correction procedure​

  1. Check that the statement begins for Counter := InitialValue.
  2. Insert exactly one direction keyword: to to increment or downto to decrement.
  3. Supply the final value after the direction.
  4. Check for the separate do keyword before the loop body.

Edge cases and quirks​

  • The public message is inherited from PascalScript and says only 'TO' expected; downto is equally valid.
  • A misspelling such as downToValue is an identifier, not the downto keyword, and triggers this diagnostic at that token.
  • Velox accepts integer-sized counters, enumeration counters and Variant counters in this compiler path. Unlike Delphi's general ordinal rule, the current counter-type check does not include Char; a character counter produces Type mismatch rather than 'TO' expected.
  • An invalid counter, initial value or final value produces Variable Expected or Type mismatch. Adding to does not correct those separate faults.
  • The initial and final expressions are compiled before the loop body. The final expression is evaluated once when the loop starts, and Velox emits a boundary check to avoid wrapping an integer counter after its highest or lowest value.
  • This is a compile-time error. The loop body does not execute partially.
  • DO expected - the loop direction is present but the body separator is missing.
  • Type mismatch - the counter or a bound has an unsupported type.
  • Variable Expected - the counter is not writable variable storage.

External references​