ml_vsa — Library by Market_Logic_India — TradingView

The idea

VSA reads each bar as EFFORT (volume) versus RESULT (the spread, and where the bar closed inside its range):

Effort with no result — heavy volume, narrow spread — is absorption: someone is soaking up orders without moving price.
Result with no effort — wide spread, light volume — is a move with nothing behind it.
A new extreme that gets rejected on volume — pushes past the prior high/low but closes back inside — is a trap (Upthrust up, Shakeout down).

Each function takes a series source (high, low, close, volume) and simple window lengths, so it drops into any study. Percentile thresholds follow standard VSA practice and are baked in; the windows are yours.

Primitives
closePos(h, l, c) — where the bar closed inside its range: 0 = on the low, 1 = on the high.
spreadPct(h, l, len) — the current bar’s range as a percentile (0..100) of its own recent history. The RESULT axis: is this a wide bar or a narrow one, for this symbol right now.
volPct(v, len) — the current bar’s volume as a percentile (0..100) of its own history. The EFFORT axis. On a volumeless symbol this is flat and the volume-gated events simply never fire.
Named events (one-bar classifications; each self-contained, each returns a bool unless noted)
noDemand(h,l,c,v,len) — bearish. An up-bar on NARROW spread and LOW volume: the rally has no effort behind it.
noSupply(h,l,c,v,len) — bullish. A down-bar on narrow spread and low volume: no selling pressure left.
upthrust(h,l,c,v,len,pivLen) — bearish. Pushes to a NEW HIGH (over the prior pivLen highs) on HIGH volume but closes back near the LOW — buyers trapped.
shakeout(h,l,c,v,len,pivLen) — bullish. Pushes to a NEW LOW on high volume but closes back near the HIGH — sellers trapped (a Spring).
stoppingVolume(h,l,c,v,len) — bullish. A WIDE down-bar on VERY HIGH volume that closes OFF the low — heavy demand stepping in to halt a decline.
climax(h,l,c,v,len) — returns +1 / −1 / 0. CLIMACTIC volume (≥90th pct) on a wide bar: an up-climax is a potential buying-climax exhaustion (returns −1, bearish); a down-climax is a selling-climax exhaustion (returns +1, bullish).
effortNoResult(h,l,v,len) — a NON-directional absorption flag. High volume, narrow spread: effort with no result. Where the market is soaking up orders; direction needs context.
Composites
vsaBias(h,l,c,v,len,pivLen) — the events netted to a direction: +1 bullish, −1 bearish, 0 none/conflict. (The non-directional absorption flag is deliberately excluded.) Use this one call so a “VSA-confirmed” read means the same thing on every engine.
vsaCode(h,l,c,v,len,pivLen) — an integer identifying WHICH event dominates (priority: climax > trap > stopping > no-demand/supply > absorption): 3 buying-climax · −3 selling-climax · 2 upthrust · −2 shakeout · −1 stopping · 4 no-demand · −4 no-supply · 5 absorption · 0 none. (The sign here identifies the event, not the trade direction — use vsaBias for direction.)
vsaLabel(h,l,c,v,len,pivLen) — the dominant event as a string (“Upthrust”, “Stopping volume”, …) for a dashboard or a marker.
How to use

Mark the events, and read a shared direction:

//version=6
indicator(“Example — VSA events”, overlay = true)
import Market_Logic_India/ml_vsa/1 as vsa

len = input.int(50, “VSA history window”)
piv = input.int(5, “New-extreme lookback”)

ut = vsa.upthrust(high, low, close, volume, len, piv)
so = vsa.shakeout(high, low, close, volume, len, piv)
sv = vsa.stoppingVolume(high, low, close, volume, len)

plotshape(ut, “Upthrust”, shape.triangledown, location.abovebar, color.red, text = “UT”)
plotshape(so, “Shakeout”, shape.triangleup, location.belowbar, color.green, text = “SO”)
plotshape(sv, “Stopping”, shape.square, location.belowbar, color.teal, text = “SV”)

bias = vsa.vsaBias(high, low, close, volume, len, piv) // +1 / -1 / 0
bgcolor(bias > 0 ? color.new(color.green, 90) : bias < 0 ? color.new(color.red, 90) : na)

The events pair naturally with level and flow tools: an Upthrust into a resistance level, or Stopping Volume on a support level, is far stronger than either read alone.

Notes
Non-repainting: every read is a pure function of closed-bar spread, volume, close and their rolling history (ta.percentrank / ta.highest / ta.lowest). Nothing looks ahead. To be certain a live bar’s event never flickers, gate on barstate.isconfirmed in your host script.
State safety: the composites call each event UNCONDITIONALLY and then select, so the ta.* inside every event runs on every bar (the correct Pine pattern). If you call the individual events yourself, keep them out of if/ternary branches for the same reason.
Types: pass series for the price/volume inputs and simple int for the window lengths.
These are OHLCV-based proxies for the classic tape reads, not exchange-grade order flow — pair every event with a forward test (e.g. ml_calib) before trusting its edge on your instrument.
Concept credits

Volume Spread Analysis and the effort-vs-result principle — with the named events No Demand, No Supply, Upthrust, Shakeout/Spring, Stopping Volume, Buying/Selling Climax and Test — descend from Richard D. Wyckoff and the VSA tradition associated with Tom Williams. This library is an original, dependency-free Pine v6 packaging of those public techniques; it is not affiliated with, nor endorsed by, any originator.

License

Mozilla Public License 2.0 — as required for TradingView libraries (open source). Free to import and build on.