Bristol Junction from Bristol Temple Meads is operated by South Western Railway, and there are scheduled coach links to most major UK cities. The M4 motorway connects the city on an east-west axis from London to West Wales, and the M5 is a north–south west axis from Birmingham to Exeter. The M49 motorway is a shortcut between the M5 in the south and the M4 Severn Crossing in the west, and the M32 is a spur from the M4 to the city centre. The Portway connects the M5 to the city centre, and was the most expensive road in Britain when
M4 (computer language) most Unix variants ship with it. m4 has many uses in code generation, but (as with any macro processor) problems can be hard to debug. m4 offers these facilities: Unlike most earlier macro processors, m4 does not target any particular computer or human language; historically, however, its development originated for supporting the Ratfor dialect of Fortran. Unlike some other macro processors, m4 is Turing-complete as well as a practical programming language. Unquoted identifiers which match defined macros are replaced with their definitions. Placing identifiers in quotes suppresses expansion until possibly later, such as when a quoted string is expanded as