Include current row in value mapping context

pkg/migrate/README.adoc

@@ -176,7 +176,8 @@ The system also provides support for arbitrary mathematical expressions.
 If you wish to perform an expression, prefix the mapped value with `=EVL=`; for example `=EVL=numFmt(cell, \"%.0f\")`.
 
 Variables:
-* current cell -- `cell`.
+* current cell -- `cell`,
+* current row -- `row`; access cell by it's name -- eg. `row.FirstName + row.LastName`.
 
 The following example will remove the decimal point from every `sys_rating` in the given source.
 

pkg/migrate/types/eval.go

@@ -3,15 +3,17 @@ package types
 import (
 	"fmt"
 	"strconv"
+	"time"
 
 	"github.com/PaesslerAG/gval"
 )
 
 // generates a simple gval language to be used within the migration
-func exprs() gval.Language {
+func Exprs() gval.Language {
 	return gval.NewLanguage(
 		gval.JSON(),
 		gval.Arithmetic(),
+		gval.PropositionalLogic(),
 
 		gval.Function("numFmt", func(number, format string) (string, error) {
 			nn, err := strconv.ParseFloat(number, 64)
@@ -21,5 +23,25 @@ func exprs() gval.Language {
 
 			return fmt.Sprintf(format, nn), nil
 		}),
+
+		gval.Function("fFmt", func(number float64, format string) (string, error) {
+			return fmt.Sprintf(format, number), nil
+		}),
+
+		// diff between two dates in seconds
+		gval.Function("dateDiff", func(d1, d2 string) (float64, error) {
+			t1, err := time.Parse(SfDateTime, d1)
+			if err != nil {
+				return 0, err
+			}
+
+			t2, err := time.Parse(SfDateTime, d2)
+			if err != nil {
+				return 0, err
+			}
+
+			dr := t2.Sub(t1)
+			return dr.Seconds(), nil
+		}),
 	)
 }

pkg/migrate/types/node.go

@@ -397,7 +397,7 @@ func importNodeSource(n *Node, users map[string]uint64, repo repository.RecordRe
 		return r
 	}
 
-	lng := exprs()
+	lng := Exprs()
 
 	for {
 	looper:
@@ -417,6 +417,12 @@ func importNodeSource(n *Node, users map[string]uint64, repo repository.RecordRe
 		}
 
 		vals := types.RecordValueSet{}
+
+		row := map[string]string{}
+		for i, h := range n.Header {
+			row[h] = record[i]
+		}
+
 		for i, h := range n.Header {
 			var values []string
 			val := record[i]
@@ -564,7 +570,7 @@ func importNodeSource(n *Node, users map[string]uint64, repo repository.RecordRe
 								return nil, err
 							}
 
-							v, err = ev.EvalString(context.Background(), map[string]interface{}{"cell": v})
+							v, err = ev.EvalString(context.Background(), map[string]interface{}{"cell": v, "row": row})
 							if err != nil {
 								return nil, err
 							}