Started working on more package docs

_docs/mod/core.md

@@ -1,7 +1,7 @@
 ---
 ---
 
-# Core Functions
+# Core Builtins
 
 ### call
 
@@ -33,15 +33,16 @@ If COL is a hash, BLOCK receives both the key and value of each element.
 
 BLOCK can call `break` and `continue` which will exit out of the loop, or jump to the start of the next iteration
 respectively.
-
 The return value of `foreach` will be the result of the last iteration, unless `break` is called with a value.
 
+This is implemented as a macro but can be used in a pipeline. 
+
 ```
 foreach [1 2 3] { |e|
   echo "Element = $e"
 }
 
-foreach [a:"one" b:"two"] { |k v|
+[a:"one" b:"two"] | foreach { |k v|
   echo "Key $k = $v"
 }
 ```

_docs/mod/csv.md

@@ -0,0 +1,29 @@
+# CSV Module
+
+Functions for operating over CSV data.
+
+### each-record
+
+```
+csv:each-record FILE BLOCK
+```
+
+Opens the CSV file at FILE and calls BLOCK on each record. It is expected that this
+CSV file has a header which appears as the first row. This command will read and
+index the header, then start calling BLOCK from the row directly below the header.
+
+BLOCK is called with the arguments _|row header|_ where:
+
+- _row_ contains the fields of the current row as a list.
+- _header_ contains a hash mapping a header name to a field index.
+
+The return value will be nil.
+
+```
+csv:each-record "winds.csv" { |row hdr|
+  set name $row.($hdr.name)
+  set bearing $row.($hdr.bearing)
+  
+  echo "Wind $name has bearing $bearing"
+}
+```

_docs/mod/fs.md

@@ -0,0 +1,11 @@
+# FS Module
+
+Functions for accessing the file system.
+
+### lines
+
+```
+fs:lines FILE
+```
+
+Returns a list containing the scanned lines of FILE.

_docs/mod/index.md

@@ -0,0 +1,8 @@
+# Modules
+
+Modules of the standard library:
+
+- [core](/mod/core): Core builtins
+- [csv](/mod/csv): Functions for operating over CSV data.
+- [fs](/mod/fs): File system functions
+- [os](/mod/os): Operating system functions 

_docs/mod/os.md

@@ -0,0 +1,17 @@
+# OS Module
+
+Functions for accessing the operating system.
+
+### env
+
+```
+os:env NAME [DEFAULT]
+```
+
+Returns the value of the environment variable NAME. If no environment with NAME
+is defined, then DEFAULT will be returned, if specified. Otherwise, nil will be
+returned.
+
+```
+echo "User's home directory is: " (os:env "HOME")
+```