Found while answering whether the C# backend still needs fglproto: a
cross-module test came out with c=3.00 where the C runtime said 3.50.
4GL division never truncates. 7/2 is 3.5 whatever the operands are
declared as, and it is the assignment afterwards that rounds or
truncates - LET i = 7/2 gives 3 because i is an INTEGER, not because
the division did anything. Checked against the C runtime:
dec 7/2 = 3.5000
flt 7/2 = 3.50
int 7/2 = 3
lit 7/2 = 3.5000
neg -7/2 = -3.5000
The generator emitted a bare C# "/", which truncates at the division
itself when both sides are integers, so a DECIMAL target held 3.00.
Division now goes through Fgl.Divide, which promotes first. Division by
zero returns NULL rather than throwing, as the C runtime does - a 4GL
program tests the result, it does not catch anything.
Two things fell out of fixing it:
assign_wrapper had no case for FLOAT or SMALLFLOAT, so assigning any
decimal-valued expression to one would not compile. It has one now,
the same shape as the CHAR, DECIMAL and SMALLINT cases.
DISPLAY of a MONEY lost its currency symbol. MONEY and DECIMAL are
both decimal? at runtime - that is deliberate, the difference is
presentational - so the type has to be named where it is still known,
and the generator now emits Fgl.DispMoney for it. The symbol comes
from DBMONEY, which can also place it after the number and change the
decimal separator, and it is extra to the declared width: a
MONEY(10,2) shows in 13 columns where a DECIMAL(10,2) shows in 12.
New end-to-end probe arith.4gl covers all of it: division into DECIMAL,
FLOAT, INTEGER and SMALLINT, negative and literal division, MONEY, and
the other three operators plus MOD.
Every result in it is assigned to a declared variable before being
displayed, deliberately. DISPLAYing a raw expression is a separate
question - an unassigned division has no declared scale, and 4GL prints
it at DECIMAL's maximum width - and that gap is recorded in the README
rather than quietly folded into this probe.
Fidelity: 27 semantics, 9 UI messages, 30 USING, the 66-line report and
6 end-to-end programs all agree with C. 203 runtime tests pass, d4 still
builds clean, and the standalone corpus is unchanged at 30 of 33.
