3.11 Pragmas

3.11 Pragmas

Most tools have to support some essential, but rather inelegant

features. In FunnelWeb these messy bits have all been stuffed

Tutorial

into the scanner s 

pragma

 (for 

pragma

 tic) construct.

A pragma consists of a single line of input (including the EOL)

Developer

commencing with @p. This must be followed by a single space,

and then the pragma verb. This must be followed by a sequence

Reference

of zero or more arguments separated by one or more spaces.

1 Introduction

Four pragmas are available

2 Interface

3 Scanner

pragma = pragma_ident | pragma_mill |

4 Parser

         pragma_moll | pragma_typesetter

5 Analyser

The following syntax definitions assist in defining the pragmas.

6 Tangle

7 Weave

s        = {" "}+

8 Shell

ps       = ("@p" | "@P") " "

9 Commands

number   = { decimal_digit }+

10 Glossary

numorinf = number | "infinity"

11 References

The arguments to pragmas are case sensitive and must be

specified in lower case.

SEARCH

Pragmas are processed and consumed entirely by the scanner.

The parser never sees them and so they can play no part in the

parser level syntax. As a result, pragma lines can appear

anywhere in the entire input file regardless of the surrounding

context (e.g. even in the middle of a macro definition). The sole

effect of a pragma is to modify some internal parameter of

FunnelWeb.

The following sections describe the four FunnelWeb pragmas.

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Copyright   Ross N. Williams 1992,1999. All rights

reserved.

http://www.ross.net/funnelweb/reference/scanner_prag.html [3/3/2000 10:47:48 PM]