Line Comments are a language feature.
Comments that start with a character and continue until end of line.
Languages without Line Comments include HTML, XML, JSON, CSS, Mathematica, Pascal, OCaml, Smalltalk, Regular Expressions, Modula-2, Standard ML, Rexx, SPSS, Markdown, Modula-3, SVG, XQuery, ML, Wolfram Language, OWL, Object Pascal
Languages with Line Comments include Java, JavaScript, C, Python, C++, SQL, PHP, Ruby, R, Go, Perl, C#, Scala, MATLAB, Swift, MySQL, Rust, Haskell, Fortran, Lua, TypeScript, Scheme, Objective-C, COBOL, Clojure, PostgreSQL, SAS, Visual Basic, Erlang, ARM, Kotlin, Prolog, Julia, Elixir, Ada, PowerShell, Tcl, Dart, Groovy, F#, CoffeeScript, Common Lisp, Bash, D, Solidity, Crystal, Racket, Nim, BASIC, APL, Delphi, Chapel, Forth, Elm, Verilog, awk, Eiffel, Reason, PostScript, Haxe, Maple, YAML, GNU Octave, LaTeX, Emacs Lisp, fish, GraphQL, Dylan, Tex, VHDL, REBOL, LLVM IR, MUMPS, Idris, Red, PureScript, Pug, Simula, PL/SQL, Zig, Applescript, Vala, BCPL, WebAssembly, ANTLR, ClojureScript, Io, Visual Basic .NET, Deno, Rust MIR, HAML, Hy, Wren, Oz, MIPS architecture, J, VBScript, Logo, Ballerina, SNOBOL, Boo, ActionScript, Hack, TOML, Yacc, V, Protocol Buffers, Sage, CIL, OpenCL, AMPL, HCL, MoonScript, Pike, AutoIt, Fantom, Icon, VBA, SPARQL, QBasic, Stata, SuperCollider, Agda, Perl 6, Scilab, Falcon, Seed7, sed, Nemerle, Ceylon, Squirrel, JSON5, PEG.js, Cap'n Proto, Makefile, Xojo, X10, Bison, FLUX, Processing, Mercury, Batchfile, ABAP, Clean, Koka, Lasso, Eve, NewLisp, PureBasic, xBase, E, Terra, Zephir, Dafny, Frege, Java Bytecode, DOT, Smali, K, KaTeX, UNLAMBDA, Guile, API Blueprint, SETL, Lean, Nginx, PRQL, ATS, LFE, AutoHotkey, Modelica, SystemVerilog, Clipper, Monkey, M4, Turing, Bicep, Ini, x86 Assembly, LiveScript, Nearley, Less, Pig Latin, Datalog, Csound, LiveCode, Hjson, PicoLisp, unison, halide, carp, JCL, NetLogo, Sather, Transact-SQL, LPC, Flow, CIL, JAI, YASnippet, odin, CLIPS, WDL, Unicon, wisp, Pony, muPad, AspectJ, HOPE, Gosu, BETA, FoxPRO, CWL, TLA, AGC, Fennel, QML, Lex, Cg, LilyPond, Objective-J, Classroom Object Oriented Language, SIL, Cryptol, PEG, NSIS, Dhall, Nit, Futhark, Observable, Euphoria, Cue, idyll, Felix, JADE, Alloy, Dc, Click, Mu, S-algol, PowerBuilder, Ring, Fancy, GLSL, datascript, Flow9, OpenSCAD, mgmt, PL/pgSQL, Java Properties, Tea, Refal, Ch, starlark, Logica, eC, BlitzBasic, NCAR Command Language, P4, Expect, Netwide Assembler, IGOR Pro, ArkScript, QB64, Angelscript, Filebench WML, Whiley, PAWN, Cypher Query Language, Aldor, DAX, SugarSS, MiniD, Apex, Gettext Catalog, Not Quite C, Action!, KiXtart, SCSS, mlir, GAP, Ragel, Ron, Golo, Volt, Augmented Backus-Naur Form, Concise Encoding, Parser 3, Pan, spry, lispyscript, clay, Dockerfile, CIR, JSL, Spatial, BlitzMax, OpenVera, Ligo, PowerQuery M, MQL5, Argdown, OX, HLSL, mun-lang, Ren'Py, SourcePawn, Ezhil, Mask, ECL, True BASIC, Harbour, popr, DM, GDScript, Frink, Cell, Gentoo Ebuild, Hocon, Mary, Vigil, Jasmin, Shen, JSON with Comments, Linden Scripting Language, Script.NET, XBase++, OCL, PowerBASIC, Strips, HiveQL, Game Maker Language, Objective C++, C shell, KRL, Rescript, EuLisp, S-PLUS, Not eXactly C, Ion, NetLinx, Opal, Praat Script, dex, Gherkin, Eclipse Command Language, Logos, Spin, Mouse, Q#, Structured Query Reporter, BitBake, storyscript, NestedText, PIC, Cycript, LookML, SMT, POV-Ray SDL, Charity, Sophia, Quaint, c3, Xbasic, Amazon Redshift, Raku, Jsonnet, parasail, Rc, BLISS, Bel, Fable, CLOS, NS Basic, FutureBASIC, spiral, neut, RELAX NG, Embedded Crystal, LoomScript, Slice, Type Language, manool, Yoix, Judoscript, Project Mentat, carth, beads-lang, Ren, Zimpl, Z, JSLT, Tuple space, Vale, ThinBasic, Redcode, Adventure Game Studio Script, CartoCSS, SRecode Template, ldpl, pointless, gentee, kai, winxed, SimCode, Language Server Index Format, owen-lang, Claro, dlvm, Lexon, Reia, Sweet Expressions, Caché Basic, FML, Literate Agda, Module Management System, Reactive Plan Language, Soy, Yedalog, VHDL-AMS, MVEL, Turbo Basic, XBLite, WxBasic, HuJSON, Grammatical Framework, Alpine Abuild, GCC Machine Description, Brightscript, ShaderLab, Nymph, tht, Fjölnir, Lite-C, silk, Heron, taf, z80, BuddyScript, ISETL, Pawn, Recfiles, fizz, Guix Workflow Language, omega, Plot, PromQL, rosette-lang, verifpal, Finite State Language, holyc, rbs, Robots.txt, SubX, Maya Embedded Language, FloScript, Wart, Yet Another Scripting Language, PROMAL, OEM, neeilang, hilvl, boa, epsilon, flagship, lain, stella, GraphQL Schema Definition Language, StruQL, turnstile, xxl, CFScript, StarOffice Basic, Savi, Easytrieve, ActiveVFP, OptimJ, Pnuts, Action Code Script, MACRO-10, Operational Control Language, Treelang, AmbientTalk, atomese, Bla, Boogie, luau, USD, wescheme, ca65 Assembly, ctalk-lang, dslx, Portable Bit Map Format, Netpbm grayscale image format, ppm-format, rbscript, taichi, tremor-query, Creative Basic, Parrot BASIC, Rita, Spice, ddfql, sora, zephyr-asdl, blz, PkgConfig, PacmanConf, Lighttpd configuration file
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