🧩 SymbolParams (GoMT4)

Goal: read symbol parameters (Digits, Point, LotStep, Min/Max lot, Stops/Freeze levels, etc.) and use them for rounding & validations.

Real code refs:

• Account: examples/mt4/MT4Account.go (SymbolParams)
• Demo: examples/mt4/MT4_service.go (see ShowSymbolParams flow)

---

✅ 1) Preconditions

• Symbol exists and is visible in MT4 (Market Watch → Show All).
• config.json has a known default symbol or you pass one explicitly.

---

🔎 2) Read params

p, err := account.SymbolParams(ctx, symbol)
if err != nil { return err }

fmt.Printf("%s: Digits=%d Point=%.10f LotStep=%.2f MinLot=%.2f MaxLot=%.2f\n",
    symbol,
    p.GetDigits(),
    p.GetPoint(),
    p.GetVolumeStep(),
    p.GetVolumeMin(),
    p.GetVolumeMax(),
)
fmt.Printf("StopsLevel=%d FreezeLevel=%d ContractSize=%.2f\n",
    p.GetStopsLevel(), p.GetFreezeLevel(), p.GetContractSize(),
)

Common fields:

• Digits —the number of decimal places in the price.
• Point — the tick value (usually `10^-Digits').
• VolumeStep — the volume step in lots.
• VolumeMin/VolumeMax — acceptable volume range.
• StopsLevel — minimum distance (in points) for SL/TP/postponement from the current price.
• FreezeLevel — the area around the current price, where modification/removal of the ban may be limited.
• ContractSize — the size of the contract (for calculating the cost of the item).

---

🧮 3) Helpers: rounding by params

func alignVolume(v, step, min, max float64) float64 {
    if step <= 0 { return v }
    v = math.Floor(v/step+0.5) * step
    if v < min { v = min }
    if v > max { v = max }
    return v
}

func roundPrice(p float64, digits int) float64 {
    mul := math.Pow10(digits)
    return math.Round(p*mul) / mul
}

Usage:

vol := alignVolume(0.13, p.GetVolumeStep(), p.GetVolumeMin(), p.GetVolumeMax())
price := roundPrice(1.092345, int(p.GetDigits()))

---

🛡️ 4) Validate SL/TP and pending price

// Distance in points from current price (Bid for SELL, Ask for BUY)
q, _ := account.Quote(ctx, symbol)

entry := q.GetAsk() // for BUY; use Bid for SELL
point := p.GetPoint()

// Desired SL/TP distances (points)
slDist := 20.0
tpDist := 40.0

sl := roundPrice(entry - slDist*point, int(p.GetDigits()))
tp := roundPrice(entry + tpDist*point, int(p.GetDigits()))

// Respect StopsLevel
if slDist < float64(p.GetStopsLevel()) || tpDist < float64(p.GetStopsLevel()) {
    return fmt.Errorf("SL/TP too close: StopsLevel=%d", p.GetStopsLevel())
}

For pending orders:

pendingPrice := roundPrice(entry - 10*point, int(p.GetDigits())) // e.g., Buy Limit
if math.Abs((entry - pendingPrice)/point) < float64(p.GetStopsLevel()) {
    return fmt.Errorf("pending too close to market: StopsLevel=%d", p.GetStopsLevel())
}

---

⚠️ Pitfalls

• Wrong precision → always round prices to Digits and volumes to VolumeStep.
• Too close SL/TP → compare distances in points with StopsLevel.
• FreezeLevel → The broker may prohibit modifications close to the price; try a little further from the market.
• Suffix mismatch → EURUSD vs EURUSD.m — different tools.

---

🔗 See also

• RoundVolumePrice.md — rendered helpers for rounding.
• PlaceMarketOrder.md / PlacePendingOrder.md — using Digits/LotStep/StopsLevel in orders.
• GetQuote.md — get the current price for calculations.