Abbreviation :

A source token whose leftmost characters exactly match the leftmost characters of a keyword in a translation directive. Abbreviations must be at least four characters in length.

Blockify :

To change an expression in the source text into a code block definition. Blockifying is accomplished by surrounding the source text with braces and placing an empty block parameter list (a pair of vertical bars) just inside the braces. When the resulting code block is evaluated at runtime, the original expression will be evaluated.

Blockify Result Marker :

A result marker of the form <{id}>. id must correspond to the name of a match marker. A blockify result marker specifies that the corresponding source text is to be blockified. If the matched source text is a list of expressions, each expression in the list is individually blockified. If no source text matched the corresponding match marker, an empty result is produced.

Conditional Compilation :

Selective exclusion by the preprocessor of certain source code. The affected source code is bracketed by the #ifdef and #endif directives. It is excluded if the argument in the #ifdef directive is not a #defined identifier.

Define :

To #define an identifier to the preprocessor and optionally specify text to be substituted for occurrences of the identifier.

Directive :

An instruction to the preprocessor. Preprocessor directives must appear on a separate line, and must begin with a hash mark (#). Their scope or effect extends from the point where they are encountered to the end of the source file in which they appear.

Dumb Stringify Result Marker :

A result marker of the form #<{id}>. id must correspond to the name of a match marker. A dumb stringify result marker specifies that the corresponding source text is to be enclosed in quotes. If the matched source text constitutes a list of expressions, each expression in the list is individually stringified. If no source text was matched, an empty pair of quotes is produced.

Empty Result :

An absence of result text; the effect of certain result markers when the corresponding match marker did not match any source text (but when the translation directive as a whole was matched). An empty result simply implies that no result text is written to output.

Header File :

A source file containing manifest constant definitions; command or pseudofunctions; and/or program statements merged into another source file using the #include preprocessor directive.

Identifier :

A name that identifies a function, procedure, variable, constant or other named entity in a source program. In Clipper language, identifiers must begin with an alphabetic character and may contain alphabetic characters, numeric characters, and the underscore character.

Include File :

A source file included another source file via #include directive. Though it is a header file by convention, pratically may be any source file.

See : Header File, source file

List Match Marker :

A match marker indicating a position that will successfully match a list of one or more arbitrarily complex expressions. A list match marker marks a part of a command that is expected to consist of a list of programmer-supplied expressions. A list match marker has the form <id,…>. id associates a name with the match marker. The name can be used in a result marker to specify how the matching source text is to be handled.

Logify :

To change an expression in the source text into a logical value. Logifying is accomplished by surrounding the expression with periods.

Logify Result Marker :

A result marker of the form #<.id.>. id must correspond to the name of a match marker. This result marker writes true (.T.) to the result text if any input text is matched; otherwise, it writes false (.F.) to the result text. The input text itself is not written to the result text.

Manifest Constant :

An identifier specified in a #define directive. The preprocessor substitutes the specified result text whenever it encounters the identifier in the source text.

Match :

A successful comparison of source text with a match pattern (or part of a match pattern).

Match Marker :

A construct used in a match pattern to indicate a position that will successfully match a particular type of source text. There are several types of match markers, each of which will successfully match a particular type of source text.

Match Pattern :

The part of a translation directive that specifies the format of source text to be affected by the directive. A match pattern generally consists of words and match markers.

Normal Stringify Result Marker :

A result marker of the form <“id”>. id must correspond to the name of a match marker. A normal stringify result marker specifies that the corresponding source text is to be enclosed in quotes. If the matched source text is a list, each element of the list is individually stringified. If no source text was matched, an empty result is produced.

Optional Clause :

A portion of a match pattern that is enclosed in square ([ ]) brackets. An optional clause specifies part of a match pattern that need not be present for source text to match the pattern. An optional clause may contain any of the components legal within a match pattern, including other optional clauses. When a match pattern contains a series of optional clauses that are immediately adjacent to each other, the matching portions of the source text are not required to appear in the same order as the clauses in the match pattern. If an optional clause is matched by more than one part of the source text, the multiple matches may be handled using a repeating clause in the result pattern.

Preprocessor :

A translation program that prepares source code for compilation by applying selective text replacements. The replacements to be made are specified by directives in the source file. In Clipper language, the preprocessor operates transparently as a part of the compiler program.

See Also : Compiler

Pseudofunction :

A function-like construct that is replaced with another expression via the #define directive, rather than compiled into a conventional function call. Pseudofunctions may contain parenthesized arguments that may be included in the substituted text.

Regular Match Marker :

A match marker indicating a position that will successfully match an arbitrarily complex expression in the source text. A regular match marker generally marks a part of a command that is expected to consist of arbitrary programmer-supplied text, as opposed to a keyword or other restrictive component. In order for the source text to match, it must constitute a properly formed expression. A regular match marker has the form <id>. id associates a name with the match marker. The name can be used in a result marker to specify how the matching source text is to be handled.

Regular Result Marker :

A result marker of the form <id>. id must correspond to the name of a match marker. This result marker writes the matched input text to the result text, or nothing if no input text is matched.

Repeating Clause :

A portion of a result pattern surrounded by square ([ ]) brackets. The text specified by the repeating clause is written to output once for each successfully matched match marker in the corresponding match pattern.

Restricted Match Marker :

A match marker indicating a position that will successfully match one or more specified keywords. A restricted match marker marks a part of a command that is expected to be a keyword. A restricted match marker has the form <id: wordList> where wordList is a list of one or more keywords. Source text is successfully matched only if it matches one of the keywords (or is an acceptable abbreviation). id associates a name with the match marker. The name can be used in a result marker to specify how the matching source text is to be handled.

Result Text :

The text that results from formatting matched source text using a result pattern. If the result text matches a match pattern in another preprocessor directive, then it becomes the source text for that directive. Otherwise, the result text is passed as input to the compiler.

Result Pattern :

The part of a translation directive that specifies the text to be substituted for source text that matches the match pattern. A result pattern generally consists of operators and result markers.

Smart Stringify Result Marker :

A result marker of the form <(id)>. id must correspond to the name of a match marker. A smart stringify result marker specifies that the corresponding source text is to be enclosed in quotes unless the source text was enclosed in parentheses. If the matched source text is a list, each element of the list is individually processed. If no source text was matched, an empty result is produced. The smart stringify result marker is used to implement commands that allow extended expressions (a part of a command that may be either an unquoted literal or a character expression).

Source Text :

Text from a source file, processed by the preprocessor. Source text is examined to see if it matches a previously specified match pattern. If so, the corresponding result pattern is substituted for the matching source text

STD.CH :

The standard header file containing definitions for all Clipper language commands.

Stringify :

To change source text into a literal character string by surrounding the text with quotes.

Text Replacement :

The process of removing portions of input text and substituting different text in its place.

Token :

An elemental sequence of characters having a collective meaning. The preprocessor groups characters into tokens as it reads the input text stream. Tokens include identifiers, keywords, constants, and operators. White space, and certain special characters, serve to mark the end of a token to the preprocessor.

Translation Directive :

A preprocessor instruction containing a translation rule. The two translation directives are #command and #translate.

Translation Rule :

The portion of a translation directive containing a match pattern followed by the special symbol (=>) followed by a result pattern.

Undefine :

To remove an identifier from the preprocessor’s list of defined identifiers via the #undefine directive.

Wild Match Marker :

A match marker indicating a position that will successfully match any source text. A wild match marker matches all source text from the current position to the end of the source line. A wild match marker has the form <*id*>. id associates a name with the match marker. The name can be used in a result marker to specify how the matching source text is to be handled.