Exec File Preprocessor Mar83

Page 1 Exec FUe Pleplo;essor Exec File Preprocessor Overview The exec file preprocessor supports a 1.111de variety of features for generating exec files, inclUding parameterization (with defaults), prorrpting for input and options, nested exec files, COITITenting, conditionals, general console IIO, aroong others. These facilities should allol.ll you to create lOOdular.. flexible exec files which are bOth pOlJlerful and easy to maintain. Essentially the preprocessor provides a language interpreter for the generation of IIJorKShop conmands. The basic operation of the exec preprocessor is as follol.lls. The preprocessor is invoked when the workShop shell recognizes a cornnand to run an exec file. The preprocessor then reads and processes its input flle( s) and creates a teflllOrary file 1111th the output it generates (which typically consists of WOrkShop directives and conmands to run other programs) . This output file 1s then passed back to the I#OrKShOp Shell for execution. After the execution of the conmands 1n the t~orary file haS terminated (either having run to completion or having raised an error) the terrporary file is deleted by the shell. Execflle input consists of tlllO types of lines -- naI1lBl lines with conmands lIIhiCh will be paSSed through to the workShop and e>eee COOII&1d lines whiCh are directed to the preprocessor (and lIIhich w111 not get paSSed to the WOrkShop). Thus, exec files actually are written in t\lO languages -- one directed to the worKShop and any programs that may be run under the worKShop, and tne other directed to the exec preprocessor i tself . So, I.IIhile the preprocessor has a ·syntlOl1c, KeYWOrd-oriented neta-l~, the underlying worKShop comnand language 1s the sane as usual, 1.e., .the KeystroKe-oriented, UCSD-style corrmand interface. That is, the exec file preprocessor provides a high level language for the generation Of worKShOp CommandS, however, it does not provide an a1 temative to the worKShop' S basic conmand language. In the rest of this cIOcunent the methOd for constructing and inVOKing exec files is described. The material is organized 1n the following sections: Exec File Invocatioo 100 Exec language E~les Exec Invocat100 ~t1oos Exec Programr1.rYJ Tips Exec Errors Fred Forsman - hOIll to run an exec file - tne exec file conmand language - sarrple exec files - options for running exec files - exec file progranming hints - errors reported by preprocessor -page 2 - page 3 - page 11 - page 15 - page 19 - page 20 March 9, 1983 Exec f!le Prepnx:essor !=Iage 2 Exec File Invocation . An invocation line for the preprocessor has the follollling form: <exec conmand> <exec file> [ «pararreter list» [ <exec options> ]] The <exec corrmand> can be either "EXECI'" or "<". The <exec file> is the name of the exec file you lIIiSh to A". TEXT" extension will be assuned if one 1s not specified; holJlever, you may override the mechanism IJIhiCh supplies the". TEXT" extension by ending your <exec file> name…