support floating point numbers

* Extends the SciTECO type system. A number on the expression stack
  or in a Q-register can be either an integer or a float.
* Floating point constants begin with a digit (like all other
  numbers), are followed by a `.` and an optional fractional part.
  Exponents cannot currently be written.
  E.g. `1.` == `1.0`. But `.0` would still be `.,0`.
  (!) To push an integer followed by dot, you must now write e.g. `1,.` or `1 .`.
* All of the basic arithmetic operators operate like this:
  If both operands are integers, the result is also an integer (integer arithmetics).
  If at least one of the operands is a float, the result is also a float (float arithmetics).
* All of the binary operators (AND, OR, XOR) always cast all
  operands to integer and the result is always an integer as well.
* You can "cast" integers to float by `*1.` or `/1.`.
  You can "cast" floats to integers using `#0`.
* Most commands still accept only integers. Floats are implicitly casted to integers.
  Float-aware commands are: =, \, ^W, Qq, Uq, %q and the conditionals.
* `%q` will not change the current type of register q.
* Numeric part of "lexer.font" is now a float (in points).
* You cannot currently print octal and hexadecimal floats.
  `==` and `===` are identical to `=` on floats.
* `===` is now printing hex integers in lower case.
  This is because SciTECO's coding style for hex constants is also lower case.
* `--with-teco-integer` renamed to `--with-teco-number`.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/parser.h b/src/parser.h
index dc43b1c..c134d94 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -443,6 +443,12 @@ typedef struct {
 	guint radix;
 	/** accumulator for parsing numbers */
 	teco_int_t value;
+	/**
+	 * if not null, value/divisor is the floating point number
+	 * FIXME: Perhaps roll this into a bitfield with radix.
+	 * The entire teco_machine_number_t could be undone.
+	 */
+	guint divisor;
 } teco_machine_number_t;
 
 /**