ZWO Minilang

Python toolkit for the ZWO minilang.

Installation

Install from PyPi with your favorite pip invocation:

$ pip install zwolang

You can confirm proper installation via the zwom CLI:

$ zwom --help
                                                                               
 Usage: zwom [OPTIONS] COMMAND [ARGS]...                                       
                                                                               
+- Options -------------------------------------------------------------------+
| --help          Show this message and exit.                                 |
+-----------------------------------------------------------------------------+
+- Commands ------------------------------------------------------------------+
| batch    Discover and convert all `*.zwom` files in the given directory.    |
| single   Convert the specified `*.zwom` file to Zwift's `*.zwo`.            |
+-----------------------------------------------------------------------------+

The ZWOM File Specification

The primary purpose of this package is to provide a simple, human-readable format for constructing Zwift workouts that can be used to generate the actual workout XML. Let's call it a *.zwom file, or ZWOM.

ZWOM files are parsed using a Parsimonious grammar, as specified below:

workout   = ((comment / block) elws*)+ / elws
block     = tag ws "{" ((comment / params) / elws)+ "}"
params    = (message / value) ","?
value     = tag ws (string / range / rangeval)

message   = "@" ws duration ws string
range     = rangeval ws "->" ws rangeval
rangeval  = duration / numeric / zone
duration  = number ":" number
percent   = number "%"
zone      = ("Z" number) / "SS"
numeric   = percent / number
elws      = ws / emptyline

comment   = ~r"\;[^\r\n]*"
tag       = ~"[A-Z_]+"
string    = ~'"[^\"]+"'
number    = ~"\d+"
ws        = ~"\s*"
emptyline = ws+

Syntax & Keywords

Like Zwift's built-in workout builder, the ZWO minilang is a block-based system. Blocks are specified using a <tag> {<block contents>} format supporting arbitrary whitespace.

Inline comments are also supported, denoted by a leading ;.

Workout Metadata

Each ZWO file must begin with a META block containing comma-separated parameters:

Keyword	Description	Accepted Inputs	Optional?
NAME	Displayed workout name	str	No
AUTHOR	Workout author	str	No
DESCRIPTION	Workout description	str1	No
FTP	Rider's FTP	int	Maybe2
TAGS	Workout tags	String of hashtags3	Yes

1. Multiline strings are supported
2. Zwift's workouts are generated using FTP percentages rather than absolute watts, so your FTP is required if you want to use absolute watts in your ZWOM
3. Tags are capped at 31 total characters, including spaces and hashtags. Zwift also provides 4 built-in tags (#RECOVERY, #INTERVALS, #FTP, and #TT) that may also be added and do not count against this total.

Workout Blocks

Following the META block are your workout blocks:

Keyword	Description
FREE	Free ride
COOLDOWN	Cooldown
INTERVALS	Intervals
RAMP	Ramp
SEGMENT	Steady segment
WARMUP	Warmup

NOTE: While there is no specific Ramp block in the workout building UI, some experimental observations have been made:

• If a Ramp is at the very beginning of the workout, Zwift serializes it as a Warmup block
• If there are multiple blocks in a workout and a Ramp is at the end, there are two paths:
  • If the left power is higher than the right power, Zwift serializes it as a Cooldown block
  • If the right power is higher than the left power, Zwift serializes it as a Ramp block
• If there are multiple blocks in a workout and a Ramp is not at the beginning nor the end, Zwift serializes it as a Ramp block

When writing your *.zwom file, these 3 blocks can be used interchangably, and ZWOM will try to match this behavior when outputting its *.zwo file. Zwift may do its own normalization if edits are made in the workout UI.

Workout Block Metadata

Workout blocks can contain the following (optionally) comma-separated parameters:

Keyword	Description	Accepted Inputs	Optional?
DURATION	Block duration	MM:SS, Range1	No
CADENCE	Target cadence	int, Range1,2	Yes
REPEAT	Number of intervals	int	Only valid for intervals
POWER	Target power	int, int%, Zone3, Range1	Mostly no4
@	Display a message	@ MM:SS str5	Yes

1. For Interval & Ramp segments, the range syntax can be used to set values for the <left> -> <right> segments (e.g. 65% -> 120% or Z2 -> Z6)
2. Cadence ranges are only valid for Interval segments
3. Zones may be specified as Z1-7 or SS
4. Power is ignored for Free segments
5. Message timestamps are relative to their containing block

Repeating a Chunk of Blocks

The START_REPEAT and END_REPEAT meta blocks are provided to specify an arbitrary chunk of blocks to repeat. The START_REPEAT block must specify a REPEAT parameter; END_REPEAT accepts no parameters. Nested repeats are not currently supported.

For example:

SEGMENT {DURATION 2:00, POWER 65%}
RAMP {
    DURATION 2:00,
    POWER 120% -> 140%,
    @ 0:00 "Here goes the ramp!",
    @ 1:50 "10 seconds left!",
}
SEGMENT {DURATION 2:00, POWER 65%}
RAMP {
    DURATION 2:00,
    POWER 120% -> 140%,
    @ 0:00 "Here goes the ramp!",
    @ 1:50 "10 seconds left!",
}

Becomes:

START_REPEAT {REPEAT 2}
SEGMENT {DURATION 2:00, POWER 65%}
RAMP {
    DURATION 2:00,
    POWER 120% -> 140%,
    @ 0:00 "Here goes the ramp!",
    @ 1:50 "10 seconds left!",
}
END_REPEAT {}

Sample Workout

; Here is a workout-level comment!
META {
    NAME "Sample Workout",
    AUTHOR "sco1",
    DESCRIPTION "Here's a description!

    Descriptions may be on more than one line too!",
    TAGS "#RECOVERY #super #sweet #workout",
    FTP 270,
}
FREE {DURATION 10:00}
INTERVALS {
    ; Here is a block-level comment!
    REPEAT 3,
    DURATION 1:00 -> 0:30,
    POWER 55% -> 78%,
    CADENCE 85 -> 110,
}
SEGMENT {DURATION 2:00, POWER 65%}
RAMP {
    DURATION 2:00,
    POWER 120% -> 140%,
    @ 0:00 "Here goes the ramp!",
    @ 1:50 "10 seconds left!",
}
FREE {DURATION 10:00}