Add more docstrings in FileCombinator

components/file_combinator.go

@@ -4,6 +4,13 @@ import (
 	"github.com/scipipe/scipipe"
 )
 
+// FileCombinator takes a set of input streams of FileIPs, and returns the same
+// number of output streams, where the FileIPs are multiplied so as to
+// guarantee that all combinations of the ips in the input streams are created.
+// Input ports and corresponding out-ports (with the same port names) are
+// created on demand, by accessing them with the p.In(PORTNAME) method.
+// The corresponding out-porta can then be accessed with the same port name
+// with p.Out(PORTNAME)
 type FileCombinator struct {
 	scipipe.BaseProcess
 	globPatterns []string
@@ -18,10 +25,8 @@ func NewFileCombinator(wf *scipipe.Workflow, name string) *FileCombinator {
 	return p
 }
 
-// Out returns the outport
-func (p *FileCombinator) Out(pName string) *scipipe.OutPort { return p.OutPort(pName) }
-
-// In returns the in-port
+// In returns the in-port with name pName. If it does not exist, it will create
+// that in-port, and a corresponding out-port with the same port name.
 func (p *FileCombinator) In(pName string) *scipipe.InPort {
 	if _, ok := p.InPorts()[pName]; !ok {
 		p.InitInPort(p, pName)
@@ -33,6 +38,9 @@ func (p *FileCombinator) In(pName string) *scipipe.InPort {
 	return p.InPort(pName)
 }
 
+// Out returns the outport
+func (p *FileCombinator) Out(pName string) *scipipe.OutPort { return p.OutPort(pName) }
+
 // Run runs the FileCombinator process
 func (p *FileCombinator) Run() {
 	defer p.CloseAllOutPorts()
@@ -62,6 +70,13 @@ func (p *FileCombinator) Run() {
 	}
 }
 
+// combine is a recursive method that creates combinations of all the IPs in the input IP arrays, such that:
+// [a.txt b.txt]
+// [1,txt 2.txt 3.txt]
+// ... will be turned into:
+// [a.txt a.txt a.txt b.txt b.txt b.txt]
+// [1.txt 2.txt 3.txt 1.txt 2.txt 3.txt]
+// as an example.
 func (p *FileCombinator) combine(inIPs map[string][]*scipipe.FileIP, keys []string) map[string][]*scipipe.FileIP {
 	if len(inIPs) <= 1 {
 		return inIPs