You can abbreviate most commands to the first letter of the command name, or for Zcommands that start with a letter, the first two letters of the command name. In the summary of each command, the full name syntax is displayed first, and the abbreviated name (if any) is displayed below it.

The summary of each command contains only textual grammar punctuation. The abstract does not include punctuation for formatting conventions, such as which elements of the grammar are optional. This information is provided in the parameter table following the summary.

One exception is the ellipsis ( ...). The ellipsis after the comma indicates that the parameter (or parameter group) before the comma can be repeated multiple times as a comma-separated list. The curly braces {the ellipsis ...} indicates that you can specify a code block containing one or more commands within the curly braces. Curly braces are literal characters that must be specified in the code.

Most commands take one or more parameters. Parameters are expressions that define or control command operations (for example, functions and their parameters, variables, operators and their operands, object properties or object methods). The multiple parameters used with a command are usually called a parameter list. Some commands have parameters themselves. For example, DOeach parameter of the command can use a parameter list. This is indicated in the grammar.

Some commands are parameterless and can be called without any parameters. Some commands never accept parameters; other commands only take parameters in certain situations. Such commands change their meaning according to whether they have no parameters or specify a parameter list.

Most commands can take an optional post-conditional expression, which specifies a condition that indicates whether the command should be executed. The post-conditional expression is :appended to the command name by a colon ( ). No spaces or newlines are allowed between the command name and its post-conditional expression. Although strictly speaking, post-conditional expressions are not command parameters, they are presented together with parameters here. No parameter commands can use post-conditional expressions.

Most ObjectScript commands are the same on all hardware platforms. Any platform-specific function of the command is marked with the type of platform that supports that function. For example, Windows or UNIX® (OpenVMS is the operating system). All platforms support any commands that are not marked as platform restrictions.

Old grammar

In most cases, old commands and functions have been replaced by newer implementations with different syntax. These commands and functions should not be used in new programming. They are recorded here as compatible with existing program code. Please note that the old commands and functions are not compatible with their replacement versions; although they may appear in the same program, they must never be combined. For example, you should not use block-oriented IFand traditional line-oriented ELSEtogether, or try to use $ZBITfunctions to manipulate $BITbit strings created by functions, or vice versa.

Legacy commands The following legacy commands have been replaced by new command syntax:

FOR
IF
ELSE
DO (Without parameters)

Traditionally IF, the ELSEand FORcommand does not use the curly brace block structure syntax. Instead, they execute commands that appear on the same program line. Therefore, they are much more restrictive in terms of row format than the updated block-oriented version of these commands.

In addition, the legacy IFcommand can not use the ELSEIFclause must use $TESTspecial variables.

The old version of no parameters DOused period prefix syntax to indicate block structure. This syntax has been superseded and is incompatible with curly brace syntax. DOThe parameterless form of is not used in future encodings.

The following old commands are obsolete:

ZQUITReplaced 为ZTRAP $ZERROR. For more details, please refer to the ZTRAPcommand.
ZSYNCOnly used for the obsolete Distributed Cache Protocol (DCP).

Preface

After two months of serialization, the basic series of "Caché Commands" has finally been serialized. Mainly give a comprehensive explanation of the current system-level commands that can be used. Reading through this topic can comprehensively improve the understanding of command usage and some rare functions. There will inevitably be flaws in the analysis of some problems. The solution in the example is not perfect, and interested friends can leave a message and discuss together after thinking about the implementation. I also hope that friends who find other problems will give feedback to the author in time.

Notice

The next issue of the series will take two to three months to serialize, "Caché Functions", Caché functions are the most commonly used and the most daily contact. But I believe that most people only know one of the functions, not the second, and there are many functions that they don’t understand. Each function has some unique and very easy-to-use usages. According to 28 principles, this "Caché Function Complete" will give a detailed overview and explanation of all functions (methods). At the beginning of each chapter, there will be a key point that I sorted out. concept.

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Caché command list

Caché command list

Caché ObjectScript commands

Routines and debugging commands

Legacy command

sequence

Old grammar

Preface

Notice

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