pgsql: pgbench: Add a real expression syntax to \set

pgbench: Add a real expression syntax to \set

Previously, you could do \set variable operand1 operator operand2, but
nothing more complicated.  Now, you can \set variable expression, which
makes it much simpler to do multi-step calculations here.  This also
adds support for the modulo operator (%), with the same semantics as in
C.

Robert Haas and Fabien Coelho, reviewed by Álvaro Herrera and
Stephen Frost

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/878fdcb843e087cc1cdeadc987d6ef55202ddd04

Modified Files
--------------
contrib/pgbench/.gitignore  |    2 +
contrib/pgbench/Makefile    |   17 +++-
contrib/pgbench/exprparse.y |   96 +++++++++++++++++++
contrib/pgbench/exprscan.l  |  105 +++++++++++++++++++++
contrib/pgbench/pgbench.c   |  215 ++++++++++++++++++++++++++++---------------
contrib/pgbench/pgbench.h   |   56 +++++++++++
doc/src/sgml/pgbench.sgml   |   17 ++--
src/tools/msvc/Mkvcbuild.pm |    1 +
8 files changed, 425 insertions(+), 84 deletions(-)