Support DB "String".

Demonstrate that it works by outputing the length of a string stored
in RAM.

compiler/compiler.go

@@ -764,6 +764,21 @@ func (p *Compiler) concatOp() {
 // dataOp embeds literal/binary data into the output
 func (p *Compiler) dataOp() {
  p.nextToken()
+
+ // We might have a string, or a series of ints
+ //
+ // If it is a string handle that first
+ if p.curToken.Type == token.STRING {
+ len := len(p.curToken.Literal)
+ for i := 0; i < len; i++ {
+ p.bytecode = append(p.bytecode, byte(p.curToken.Literal[i]))
+ }
+ return
+ }
+
+ //
+ // Otherwise we expect a single int
+ //
  db := p.curToken.Literal
  i, _ := strconv.ParseInt(db, 0, 64)
  p.bytecode = append(p.bytecode, byte(i))

examples/peek-strlen.in

@@ -0,0 +1,39 @@
+#
+# This example uses `peek` to read a string character by character
+# and output the length of that string.
+#
+# Unfortunately we can't output the string itself as we have no
+# "print character" option.
+#
+#
+
+ #
+ # #1 -> Address of string
+ #
+ # #0 -> Read each byte here
+ #
+ # #3 -> Length of string
+ #
+
+ store #3, 0x0000
+ store #1, string
+:loop
+ peek #0, #1
+ inc #1
+ inc #3
+ cmp #0, 0x00
+ jmpnz loop
+
+ # length will be one too many - so decrease by one
+ dec #3
+
+ store #1, "The length of the string is "
+ print_str #1
+ print_int #3
+ store #1, " bytes\n"
+ print_str #1
+ exit
+
+:string
+ DB "Steve"
+ DB 0x00