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, 37 insertions, 7 deletions

diff --git a/src/sciteco.h b/src/sciteco.h
index 88078c2..9d34d50 100644
--- a/src/sciteco.h
+++ b/src/sciteco.h
@@ -23,19 +23,49 @@
 
 #include <Scintilla.h>
 
-#if TECO_INTEGER == 32
+#if TECO_NUMBER == 32
+
 typedef gint32 teco_int_t;
-#define TECO_INT_MODIFIER G_GINT32_MODIFIER
-#define TECO_INT_FORMAT   G_GINT32_FORMAT
-#elif TECO_INTEGER == 64
+#define TECO_INT_MODIFIER	G_GINT32_MODIFIER
+#define TECO_INT_FORMAT		G_GINT32_FORMAT
+
+typedef gfloat teco_float_t;
+#define TECO_FLOAT_MODIFIER	""
+#define TECO_FLOAT_FORMAT	"g"
+
+#elif TECO_NUMBER == 64
+
 typedef gint64 teco_int_t;
-#define TECO_INT_MODIFIER G_GINT64_MODIFIER
-#define TECO_INT_FORMAT   G_GINT64_FORMAT
+#define TECO_INT_MODIFIER	G_GINT64_MODIFIER
+#define TECO_INT_FORMAT		G_GINT64_FORMAT
+
+typedef gdouble teco_float_t;
+#define TECO_FLOAT_MODIFIER	"l"
+#define TECO_FLOAT_FORMAT	"lg"
+
 #else
-#error Invalid TECO integer storage size
+
+#error Invalid TECO number storage size
+
 #endif
 
 /**
+ * A number cell - either integer or float.
+ * The tagging is stored outside (either in
+ * a flag or on the operator stack).
+ */
+typedef union {
+	teco_int_t	i;
+	teco_float_t	f;
+} teco_number_t;
+
+/*
+ * FIXME: The storage size of float and double are not guaranteed
+ * to be 32-bit and 64-bit.
+ */
+//G_STATIC_ASSERT(sizeof(teco_number_t) == sizeof(teco_int_t));
+
+/**
  * A TECO boolean - this differs from C booleans.
  * See teco_is_success()/teco_is_failure().
  */