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_docs/mod/core.md

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+---
+---
+
+# Core Builtins
+
+### call
+
+```
+call BLOCK [ARGS...]
+```
+
+Invokes block, passing in the arguments. This is as if block was invoked as a command. This may not always be necessary
+unless these are need to call BLOCK with exactly 0 arguments.
+
+### echo
+
+```
+echo [ARGS...]
+```
+
+Displays the string representation of ARGS to stdout followed by a new line.
+
+### foreach
+
+```
+foreach COL BLOCK
+```
+
+Iterates BLOCK over every element of the sequence.
+
+The values pass to BLOCK will depend on the type of COL. If COL is a list, BLOCK receives the element value.
+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"
+}
+
+[a:"one" b:"two"] | foreach { |k v|
+  echo "Key $k = $v"
+}
+```
+
+## index
+
+```
+index COL [INDEX...] 
+```
+
+Returns the index value at INDEX of COL. COL can be either a list or a hash.
+
+### keys
+
+```
+keys HASH
+```
+
+Returns the keys of the passed in hash as a list. The order of keys are non-deterministic.
+If HASH is not a hash, then nil will be returned.
+
+### len
+
+```
+len COL
+```
+
+Returns the length of COL. If COL is a list or hash, COL will be the number of
+elements. If COL is a string, COL will be the string's length. All other values will
+return a length of 0.
+
+### map
+
+```
+map COL BLOCK
+```
+
+Returns a new list of elements mapped from COL according to the result of BLOCK. COL can be any listable data
+structure, however the result will always be a concrete list.
+
+```
+map [1 2 3] { |x| str $x | len }
+```
+
+### proc
+
+```
+proc [NAME] BLOCK
+```
+
+Defines a new function optionally with the given name. When called without NAME, this will define a new
+lambda which can be invoked using `call`.
+
+When NAME is set, this function defining a function a name will always declare it at the top-level scope.
+
+### reduce
+
+```
+reduce COL [INIT] BLOCK
+```
+
+Returns the result of reducing the elements of COL with the passed in block.
+
+BLOCK will receive at least two argument, with the current value of the accumulator always being the last argument.
+If COL is a list, the arguments will be _|element accumulator|_, and if COL is a hash, the arguments will be
+_|key value accumulator|_. 
+
+The block result will be set as the value of the accumulator for the next iteration. Once all elements are process
+the accumulator value will be returned as the result of `reduce`.
+
+If INIT is not set, and COL is a list, the accumulator will be set to the first value and BLOCK will be called
+from the second element, if any. If COL is a hash, then the accumulator will be set to nil.
+
+## seq
+
+```
+seq [FROM] TO [-inc]
+```
+
+Returns a listable sequence containing all the integers from 0 to TO, exclusive.
+TO can be either be negative or positive. If TO Is positive, then the sequence will
+step by +1; if TO is negative, then the sequence will step by -1.
+
+If FROM is specified, then the collection contains all the integers from FROM inclusive, to TO
+exclusive. The step will be +1 or -1 if TO is greater than, or less than FROM respectively.
+
+If FROM and TO are equal, or if FROM is unspecified and TO is 0, then the sequence will be empty.
+
+If -inc is specified, then the sequence will step towards TO inclusively.
+
+```
+foreach (seq 5) { |i|
+  echo $i
+}
+```
+
+### set
+
+```
+set NAME VALUE
+```
+
+Sets the value of variable NAME to VALUE. Any variable with NAME will be checked
+within the scope first, including any parent scopes, before a new variable is defined.
+Any new variables will only be defined with the current scope.
+

_docs/mod/csv.md

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+# 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

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+# 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

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+# 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

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+# 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")
+```