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, 51 insertions, 17 deletions

diff --git a/doc/sciteco.7.template b/doc/sciteco.7.template
index fd909f9..b6b0795 100644
--- a/doc/sciteco.7.template
+++ b/doc/sciteco.7.template
@@ -999,9 +999,9 @@ two prefix arguments and returning at most one value for the next command
 into a much more elaborate scheme where commands accept
 .I n
 arguments and return
-.I n
+.I m
 arguments.
-This is done using an integer value stack.
+This is done using a number value stack.
 The stack is used for passing arguments and for arithmetics.
 \*(ST is thus a stack-based language.
 Nevertheless unary prefix and binary infix operators including operator
@@ -1009,11 +1009,25 @@ preference are supported.
 Since the same stack is used for arithmetics and command arguments,
 arithmetics and arbitrary code may be freely mixed like in
 expression-centered languages and some classic TECOs.
-For the sake of macro portability all integers are 64-bit signed
-integers regardless of the host's architecture.
-The integer storage size may be changed at \*(ST build time
+For the sake of macro portability all numbers are 64-bit wide
+regardless of the host's architecture.
+The number storage size may be changed at \*(ST build time
 however.
-In this specific build, integers are @TECO_INTEGER@-bit.
+In this specific build, numbers are @TECO_NUMBER@-bit.
+.LP
+.SCITECO_TOPIC integer float
+A \*(ST number can be either a signed integer or floating point
+number \(em it is dynamically typed.
+Integer constants create integers and floating point constants
+create floats.
+Operators create integers if all operands are integers,
+while a single float operand has a float result as well.
+As an exception, the binary operators (AND, OR, XOR)
+will always cast float operands to integers discarding the fractional
+part of the number.
+If a command takes only integer arguments, as is currently the
+case for all commands accepting buffer positions and line counts,
+float arguments will be automatically casted to integers.
 .LP
 .SCITECO_TOPIC bool boolean
 Some commands expect or return booleans, most often signifying
@@ -1031,7 +1045,7 @@ command.
 .SS Constants
 .SCITECO_TOPIC constants decimal octal hexadecimal
 .
-All integer constants have to begin with a digit from 0 to 9.
+All number constants have to begin with a digit from 0 to 9.
 Constants beginning with 0 are octal constants where every digit
 represents 3 bits \(em similar to C (e.g. \(lq033\(rq is decimal 27).
 Digits 8 and 9 are not allowed in octal constants.
@@ -1052,7 +1066,19 @@ decimal.
 Digits larger than or equal to the current radix are not allowed in
 constants.
 .LP
-A complete constant is pushed on the number stack.
+A \(lq.\(rq in a number constant separates the integer and fractional
+parts of a floating point number.
+The integer part is always required, while the fractional part is optional.
+\(lq1.\(rq is therefore equivalent to \(lq1.0\(rq and does \fBnot\fP
+push 1 and the current buffer position (dot) to the stack \(em you can
+insert explicit commas if you would like to do that (\(lq1,.\(rq).
+Floating point constants cannot currently contain exponents.
+Floating point constants beginning with \(lq0.\(rq are not octal.
+\# But ^O0.333 would be. You can also write e.g. @0ff.ff for hexadecimal
+\# floating point constants. But this is pretty useless to my knowledge.
+.LP
+A complete constant is pushed on the number stack, either as an integer
+or float.
 \# Mention the minus operator?
 \# It's not technically part of the number syntax.
 Since whitespace characters will also terminate integer constants
@@ -1068,10 +1094,14 @@ precedence:
 .SCITECO_TT 90n
 .TS
 box,tab(;);
-L LX.
+L | LX | L.
+Operator;Description;Types
+_
 \fIbase\fB ^* \fIpower\fR;T{
 .SCITECO_TOPIC ^* power
 Raise \fIbase\fP to \fIpower\fP.
+T};T{
+integers and floats
 T}
 =
 \fIa\fB ^/ \fIb\fR;T{
@@ -1079,40 +1109,42 @@ T}
 Remainder of \fIa\fP divided by \fIb\fP.
 It is actually a modulo operation conforming to the
 host C compiler's modulo semantics.
-T}
+T};\^
 \fIa\fB / \fIb\fR;T{
 .SCITECO_TOPIC / divide slash
 Divide \fIa\fP by \fIb\fP.
 Naturally it is a division without remainder.
-T}
+T};\^
 \fIa\fB * \fIb\fP;T{
 .SCITECO_TOPIC * multiply asterisk
 Multiply \fIa\fP by \fIb\fP.
-T}
+T};\^
 =
 \fIa\fB - \fIb\fP;T{
 .SCITECO_TOPIC - subtract minus
 Subtract \fIb\fP from \fIa\fP.
-T}
+T};\^
 \fIa\fB + \fIb\fP;T{
 .SCITECO_TOPIC + add plus
 Add \fIb\fP to \fIa\fP.
-T}
+T};\^
 =
 \fIa\fB & \fIb\fP;T{
 .SCITECO_TOPIC & and ampersand
 Binary AND.
+T};T{
+integers
 T}
 =
 \fIa\fB ^# \fIb\fP;T{
 .SCITECO_TOPIC ^# xor
 Binary exclusive OR (XOR).
-T}
+T};\^
 =
 \fIa\fB # \fIb\fP;T{
 .SCITECO_TOPIC # or hash
 Binary OR.
-T}
+T};\^
 .TE
 .SCITECO_TT_END SP
 .LP
@@ -1508,8 +1540,10 @@ it toggles the order of word vs. non-word characters that are skipped or deleted
 .SCITECO_TOPIC Q-Register
 .
 \*(ST may store data in so called Q-Registers.
-Each Q-Register cell has an integer and string part (can store
+Each Q-Register cell has a number and string part (can store
 both at the same time).
+A number is either an integer or a floating point number (only
+one at a time).
 Strings are actually Scintilla documents.
 Therefore Q-Register strings may be edited just like buffers
 (see \fBEQ\fP command).