DOCS: Reflect the changes in import expressions.

Update the docs to remove the import statement and add the import
expression.

adds: #28

docsite/site/content/reference/expressions.md

@@ -210,6 +210,22 @@ let copiedtpl = nestedtpl{
 };
 ```
 
+Import Expressions
+------------------
+
+Import expressions bring in a ucg file and expose their bound values as a tuple
+in the current file. Import expressions are idempotent and cached so you can
+use them than once in a file safely. Import expressions start with the `import`
+keyword and are followed by a string containing the path of the file to import.
+
+```
+// You can import an entire file into the namespace.
+let imported = import "some_file.ucg";
+
+// Or you can just import a single value from that file.
+let imported_val = (import "some_file.ucg").val;
+```
+
 Format Expressions
 ----------
 

docsite/site/content/reference/grammar.md

@@ -153,11 +153,17 @@ range_expr: expr, ':', [int, ':'], expr ;
 include_expr: include_keyword, bareword, str ; 
 ```
 
+#### Import expression
+
+```
+import_expr: import_keyword, str ;
+```
 #### Non Operator Expression
 
 ```
 non_operator_expr: literal
                    | grouped
+                   | import_expr
                    | macrodef
                    | module_def
                    | format_expr
@@ -195,13 +201,11 @@ expr: binary_expr | non_operator_expr ;
 
 ```
 let_statement: let_keyword, bareword, equal, expr ;
-import_statement: import_keyword, str, as_keyword, bareword ;
 out_statement: out_keyword, bareword, str ;
 assert_statement: assert_keyword, pipe, { statement }, pipe ;
 simple_statement: expr ;
 
 statement: ( let_statement
-             | import_statement
              | out_statement
              | assert_statement
              | simple_statement ), semicolon ;

docsite/site/content/reference/statements.md

@@ -25,27 +25,14 @@ Named Value Statements
 
 ### Let statements
 
-There are two statements that can introduce a named value for a given UCG file. Let 
+There is one statement that can introduce a named value for a given UCG file,
-statements and import statements. Any collisions in binding names inside a file are 
+the let statement. Any collisions in binding names inside a file are treated as
-treated as compile errors. Bindings are immutable and once bound they can't be 
+compile errors. Bindings are immutable and once bound they can't be modified.
-modified.
 
 ```
 let name = "foo";
 ```
 
-### Import Statement
-
-The import statement imports the contents of another UCG file into the current file 
-with a name. The imported file's named values are exposed as a tuple in the referencing 
-file. It starts with the `import` keyword and is followed by a quoted path to the UCG 
-file, the keyword `as`, and a name for the imported values.
-
-```
-import "dbconfigs.ucg" as dbconfigs;
-let mysqlconf = dbconfigs.mysql;
-```
-
 Output Statements
 -----------