Combines sum and product into an arithmetic state that contains a function for it's operation

Creates arithmetic.go which will house all of these functions

1 files changed, 87 insertions, 0 deletions

diff --git a/subex/arithmetic.go b/subex/arithmetic.go
new file mode 100644
index 0000000..7200ac7
--- /dev/null
+++ b/subex/arithmetic.go
@@ -0,0 +1,87 @@
+package subex
+
+import (
+	"main/walk"
+	"errors"
+	"strconv"
+)
+
+func sumValues(atoms []walk.Atom) ([]walk.Atom, error) {
+	allBools := true
+	var sum float64 = 0
+	var any bool = false
+	values, err := walk.MemoryCompound(atoms)
+	if err != nil {
+		return nil, err
+	}
+	for _, value := range values {
+		switch v := value.(type) {
+			case walk.ValueNull:
+				allBools = false
+			case walk.ValueBool:
+				if bool(v) {
+					sum += 1
+					any = true
+				}
+			case walk.ValueNumber:
+				allBools = false
+				sum += float64(v)
+			case walk.ValueString:
+				allBools = false
+				num, err := strconv.ParseFloat(string(v), 64)
+				if err == nil {
+					sum += num
+				} else {
+					return nil, errors.New("Tried to sum non-castable string")
+				}
+			default:
+				return nil, errors.New("Tried to sum non-number")
+		}
+	}
+	if allBools {
+		return []walk.Atom{walk.ValueBool(any)}, nil
+	} else {
+		return []walk.Atom{walk.ValueNumber(sum)}, nil
+	}
+}
+
+// Compounds atoms into values, if all values are booleans, does AND, if not, tries to cast to numbers and multiply
+func multiplyValues(atoms []walk.Atom) ([]walk.Atom, error) {
+	allBools := true
+	var product float64 = 1
+	var all bool = false
+	values, err := walk.MemoryCompound(atoms)
+	if err != nil {
+		return nil, err
+	}
+	for _, value := range values {
+		switch v := value.(type) {
+			case walk.ValueNull:
+				allBools = false
+				product *= 0
+			case walk.ValueBool:
+				if !bool(v) {
+					product *= 0
+					all = false
+				}
+			case walk.ValueNumber:
+				allBools = false
+				product *= float64(v)
+			case walk.ValueString:
+				allBools = false
+				num, err := strconv.ParseFloat(string(v), 64)
+				if err == nil {
+					product *= num
+				} else {
+					return nil, errors.New("Tried to sum non-castable string")
+				}
+			default:
+				return nil, errors.New("Tried to sum non-number")
+		}
+	}
+	if allBools {
+		return []walk.Atom{walk.ValueBool(all)}, nil
+	} else {
+		return []walk.Atom{walk.ValueNumber(product)}, nil
+	}
+}