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DOCS: Modify the docs to reflect macros as closures.

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Jeremy Wall 2019-01-14 18:28:23 -06:00
parent 685ee7407e
commit 44d6247b46
3 changed files with 16 additions and 12 deletions
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10
docsite/site/content/_index.md
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@ -2,10 +2,12 @@
title = "Introduction to UCG" title = "Introduction to UCG"
in_seach_index = true in_seach_index = true
+++ +++
[UCG](https://crates.io/crates/ucg) is a universal grammar for configuration. It's goal is not to define a configuration format
like JSON, YAML, or TOML. It is not intended to replace the other configuration formats. Instead [UCG](https://crates.io/crates/ucg) is a universal grammar for configuration.
it is intended to provide a common grammar for generating those formats. Currently UCG is able to It's goal is not to define a configuration format like JSON, YAML, or TOML. It
generate conversions for the following formats. is not intended to replace the other configuration formats. Instead it is
intended to provide a common grammar for generating those formats. Currently
UCG is able to generate conversions for the following formats.
* Environment Variables * Environment Variables
* Command Line Flags * Command Line Flags

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docsite/site/content/reference/_index.md
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@ -9,7 +9,7 @@ An Overview
----------- -----------
UCG is a language specialized for generating configurations. It does not have classes, UCG is a language specialized for generating configurations. It does not have classes,
inheritance, closures, or a full type system. All values are immutable once bound to inheritance, or a full type system. All values are immutable once bound to
a name. A valid UCG file is composed of a series of statements. Statements can be a name. A valid UCG file is composed of a series of statements. Statements can be
an expression, introduce named bindings, or create different outputs. All statements an expression, introduce named bindings, or create different outputs. All statements
must be terminiated by a semicolon. must be terminiated by a semicolon.

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docsite/site/content/reference/expressions.md
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@ -407,25 +407,27 @@ Macros
----- -----
Macros look like functions but they are resolved at compile time and Macros look like functions but they are resolved at compile time and
configurations don't execute so they never appear in output. Macros do not configurations don't execute so they never appear in output. Macros close over
close over their environment so they can only reference values defined in their their environment in the file they are declared in. They are useful for
arguments. They can't refer to bindings or other macros defined elsewhere. They constructing tuples of a certain shape or otherwise promoting data reuse. You
are useful for constructing tuples of a certain shape or otherwise promoting define a macro with the `macro` keyword followed by the arguments in
data reuse. You define a macro with the `macro` keyword followed by the parentheses, a `=>`, and then a tuple literal.
arguments in parentheses, a `=>`, and then a tuple literal.
``` ```
let mymacro = macro (arg1, arg2) => { let mymacro = macro (arg1, arg2) => {
host = arg1, host = arg1,
port = arg2, port = arg2,
connstr = "couchdb://@:@" % (arg1, arg2), connstr = "couchdb://@:@" % (arg1, arg2),
} };
let my_dbconf = mymacro("couchdb.example.org", "9090"); let my_dbconf = mymacro("couchdb.example.org", "9090");
let my_dbhost = dbconf.host; let my_dbhost = dbconf.host;
``` ```
Note that while macros can close over their environment they can not reference
other fields in the macro body itself.
Modules Modules
------- -------