?whatIf

cmd/clitest/index.html

@@ -73,6 +73,11 @@
           <input name="predictFixedGrowth" type="text" value="VBTLX=0.02&predictFixedGrowth=GLD=0.02&predictFixedGrowth=FXAIX=0.03&predictFixedGrowth=FSPSX=0.03"/>
         </span>
 
+        <span>
+          <label for="whatIf">whatIf</label>
+          <input name="whatIf" type="text" value="AssetAccount:Cash $ -1.00"/>
+        </span>
+
         <span>
           <input type="submit"/>
         </span>

cmd/clitest/main.go

@@ -93,11 +93,31 @@ func main() {
 				foolike = like
 			}
 
-			register := deltas.Like(foolike...).Register()
+			deltas := deltas.Like(foolike...)
+
+			// MODIFIERS
+			for i, whatIf := range r.URL.Query()["whatIf"] {
+				fields := strings.Fields(whatIf)
+				date := "2001-01"
+				name := fields[0]
+				currency := ledger.Currency(fields[1])
+				value, err := strconv.ParseFloat(fields[2], 64)
+				if err != nil {
+					panic(err)
+				}
+				deltas = append(deltas, ledger.Delta{
+					Date:        date,
+					Name:        name,
+					Value:       value,
+					Currency:    currency,
+					Description: fmt.Sprintf("?whatIf[%d]", i),
+				})
+			}
+
+			register := deltas.Register()
 			predicted := make(ledger.Register)
 			bpis := maps.Clone(bpis)
 
-			// MODIFIERS
 			if predictionMonths, err := strconv.ParseInt(r.URL.Query().Get("predictionMonths"), 10, 16); err == nil && predictionMonths > 0 {
 				window := time.Hour * 24.0 * 365.0 / 12.0 * time.Duration(predictionMonths)
 				// TODO whatif