arf/analyzer/analyzer.go

package analyzer

import "os"
import "path/filepath"
import "git.tebibyte.media/arf/arf/types"
import "git.tebibyte.media/arf/arf/parser"
import "git.tebibyte.media/arf/arf/infoerr"

// AnalysisOperation holds information about an ongoing analysis operation.
type AnalysisOperation struct {
	sectionTable SectionTable
	modulePath   string

	trail types.Stack[locator]
}

// Analyze performs a semantic analyisys on the module specified by path, and
// returns a SectionTable that can be translated into C.
func Analyze (modulePath string, skim bool) (table SectionTable, err error) {
	if modulePath[0] != '/' {
		cwd, _ := os.Getwd()
		modulePath = filepath.Join(cwd, modulePath)
	}

	analyzer := AnalysisOperation {
		sectionTable: make(SectionTable),
		modulePath:   modulePath,
	}

	err = analyzer.analyze()
	table = analyzer.sectionTable
	return
}

// analyze performs an analysis operation given the state of the operation
// struct.
func (analyzer *AnalysisOperation) analyze () (err error) {
	tree, err := parser.Fetch(analyzer.modulePath, false)
	sections := tree.Sections()

	for !sections.End() {
		_, err = analyzer.fetchSection(locator {
			modulePath: analyzer.modulePath,
			name: sections.Value().Name(),
		})
		sections.Next()
	}
	
	return
}

// fetchSection returns a section from the section table. If it has not already
// been analyzed, it analyzes it first. If the section does not actually exist,
// a nil section is returned. When this happens, an error should be created on
// whatever syntax tree node "requested" the section be analyzed.
func (analyzer *AnalysisOperation) fetchSection (
	where locator,
) (
	section Section,
	err error,
) {
	var exists bool
	section, exists = analyzer.sectionTable[where]
	if exists { return }

	// fetch the module. since we already have our main module parsed fully
	// and not skimmed, we can just say "yeah lets skim stuff here".
	var tree parser.SyntaxTree
	tree, err = parser.Fetch(where.modulePath, true)
	if err != nil {
		section = nil
		return
	}

	var parsedSection = tree.LookupSection(where.name)
	if parsedSection == nil {
		section = nil
		return
	}

	// FIXME: this does not take into account, for instance, recursive
	// functions or objects that have pointers to themselves.
	for _, plate := range analyzer.trail {
		if plate == where {
			parsedSection.NewError (
				"cannot have cyclic section dependency",
				infoerr.ErrorKindError)
			return
		}
	}
	
	analyzer.trail.Push(where)
	defer analyzer.trail.Pop()

	// TODO: analyze section
	switch parsedSection.Kind() {
	case parser.SectionKindType:
	case parser.SectionKindObjt:
	case parser.SectionKindEnum:
	case parser.SectionKindFace:
	case parser.SectionKindData:
	case parser.SectionKindFunc:
	}
	
	analyzer.sectionTable[where] = section
	return
}