flex lexer - How does a lex file (myscanner.l) works, is it token by token, char by char -


i see iteration of text scan on lex file, or lex.yy.c file in case.

the lexical scanner reads input character @ time, , when recognizes token. if user-defined action includes return, yylex returns @ point, otherwise continues scanning find next token (which happen if yylex called again after user action returns.)

it possible lexical scanner have read far ahead while trying identify token, because token might prefix of longer potential token turns out not matched remaining input. in case, scanner reset scan end of identified token.

if build lexical scanner -d (debug) option , link -lfl, should able see of significant scanner actions in debugging traces. if that's not sufficient needs (or curiosity), i'd suggest using debugger.


Comments

Post a Comment

Popular posts from this blog

routing - AngularJS State management ->load multiple states in one page -

Image
i developing site in angularjs ui-router. have situation on button click need change , load 3 state page , 3 looks image .please me how can load multiple pages. in 1 page you need configure router config this: $stateprovider .state("state1", { url: "/url1", controller: "firstcontroller", views: { view1: { templateurl: "templates/template1.html" }, view2: { templateurl: "templates/template2.html" }, view3: { templateurl: "templates/template3.html" } } }).state("state2", { url: "/url2", controller: "secondcontroller", views: { view1: { templateurl: "templates/template4.html" }, view2: { templateurl: "templates/template5.html" }, view3: { templateurl: "templates/template6.html" } }).state("state3", { ...
Read more

python - GRASS parser() error -

i'm trying use grass on python 2.7, i'm having problems @ setting script on idle, i'm getting error @ parser() function: here script: import os import sys gisbase = os.environ['gisbase'] = 'c:\program files (x86)\grass gis 7.0.1rc1' gisrc = 'c:\grassdata' gisdbase = 'c:\grassdata' location = 'newlocation' mapset = 'tc' ld_library_path = 'c:\program files (x86)\grass gis 7.0.1rc1\lib' path = 'c:\program files (x86)\grass gis 7.0.1rc1\etc';'c:\program files (x86)\grass gis 7.0.1rc1\etc\python';'c:\program files (x86)\grass gis 7.0.1rc1\lib';'c:\program files (x86)\grass gis 7.0.1rc1\bin';'c:\python27';'c:\program files (x86)\grass gis 7.0.1rc1\python27';'c:\program files (x86)\grass gis 7.0.1rc1\msys' pythonlib = 'c:\python27' pythonpath = 'c:\program files (x86)\grass gis 7.0.1rc1\etc\python' sys.path.append(os.path.join(os.environ['...
Read more

Swift game error message -

i following ios game tutorial. cannot figure out wrong here. error on these 2 lines. let newangle = percent * 180 - 180 cannon.zrotation = cgfloat(newangle) * cgfloat(m_pi); 180.0 //error "use of unresolved identifier 'percent'" the tutorial uses: cannon.zrotation = cgfloat(newangle) * cgfloat(m_pi)/ 180.0 but changed error suggested import spritekit class gamescene: skscene { var cannon: skspritenode! var touchlocation:cgpoint = cgpointzero override func didmovetoview(view: skview) { /* setup scene here */ cannon = self.childnodewithname("cannon") as! skspritenode } override func touchesbegan(touches: set<uitouch>, withevent event: uievent?) { /* called when touch begins */ touchlocation = touches.first!.locationinnode(self) } override func touchesmoved(touches: set<uitouch>, withevent event: uievent?) { touchlocation = touches.first!.locationinn...
Read more