v/vlib/v
Delyan Angelov 5a231326d7
parser: improve syntax errors in module declarations
2021-03-11 10:42:36 +02:00
..
ast checker: allow accessing fields common to all sumtype members (#9201) 2021-03-09 19:16:18 +02:00
builder os: deprecate os.exec (returning ?os.Result), in favour of os.execute, which returns os.Result (#8974) 2021-03-08 20:52:13 +02:00
cflag
checker parser: improve syntax errors in module declarations 2021-03-11 10:42:36 +02:00
depgraph
doc vdoc: fix symbol filtering (#9210) 2021-03-09 13:05:50 +02:00
embed_file
errors
eval
fmt v.util: add util.tabs() (#9211) 2021-03-09 13:03:25 +02:00
gen v: support `$if prod` (#9228) 2021-03-10 19:26:34 +02:00
live os: deprecate os.exec (returning ?os.Result), in favour of os.execute, which returns os.Result (#8974) 2021-03-08 20:52:13 +02:00
markused v: support dump(expr) (#9160) 2021-03-06 18:09:28 +01:00
parser parser: improve syntax errors in module declarations 2021-03-11 10:42:36 +02:00
pkgconfig
pref v: fix `[if debug] fn abc(){} ... abc()` 2021-03-07 12:05:07 +02:00
preludes
scanner v.scanner: fix position of hash statements (#9222) 2021-03-10 20:23:17 +02:00
table checker: allow accessing fields common to all sumtype members (#9201) 2021-03-09 19:16:18 +02:00
tests v: support `$if prod` (#9228) 2021-03-10 19:26:34 +02:00
token v: support dump(expr) (#9160) 2021-03-06 18:09:28 +01:00
util v.util: change naming behaviour for modules relative to working dir. closes #9138 2021-03-10 16:28:06 +11:00
vcache fmt: write empty or blocks the same as empty fn bodies, empty structs, etc (#9136) 2021-03-06 21:04:51 +02:00
vet
vmod v: support dump(expr) (#9160) 2021-03-06 18:09:28 +01:00
README.md
compiler_errors_test.v os: deprecate os.exec (returning ?os.Result), in favour of os.execute, which returns os.Result (#8974) 2021-03-08 20:52:13 +02:00

README.md

Compiler pipeline

A simple high level explanation how the compiler pipeline (parser -> checker -> generator) works.

Reading files

Getting builtin files

To load all builtin files, a preference Preferences.lookup_path for the path where to look for exists. See Builder.get_builtin_files as example. If the file is a .vsh file and the backend is C, vlib/os will also be loaded as builtin.

Getting project files

Either there is a specific file: my_file.v or a directory containing V files. In the last case it scans that directory for all files. See Builder.v_files_from_dir as the helper method. This list of files needs to be filtered so that only *.v files exist.

Skips the following file types:

  • *_test.v
  • either *.c.v or *.c.js depending on the backend
  • all files that doesn't end with .v
  • Files that are not defined in Preferences.compile_defines or Preferences.compile_defines_all if any file is defined.

Parsing files

To parse something a new template is created as the first step:

import v.table

table := table.new_table()

a new preference is created:

import v.pref

pref := &pref.Preferences{}

and a new scope is created:

import v.ast

scope := ast.Scope{
	parent: 0
}

after that, you can parse your files.

Parse text

If you want to parse only text which isn't saved on the disk you can use this function.

import v.parser

code := ''
// table, pref and scope needs to be passed as reference
parsed_file := parser.parse_text(code, table, .parse_comments, &pref, &scope)

Parse a single file

For parsing files on disk, a path needs to be provided. The paths are collected one step earlier.

import v.parser

path := ''
// table, pref and scope needs to be passed as reference
parsed_file := parser.parse_file(path, table, .parse_comments, &pref, &scope)

Parse a set of files

If you have a batch of paths available which should be parsed, there is also a function which does all the work.

import v.parser

paths := ['']
// table, pref and scope needs to be passed as reference
parsed_files := parser.parse_files(paths, table, &pref, &scope)

Parse imports

A file often contains imports. These imports might need to be parsed as well. The builder contains a method which does this: Builder.parse_imports.

If the module which is imported isn't parsed already, you have to collect it relatively from the main file. For this the ast.File contains a list of imports. Those imports needs to be found on disk. . is just replaced with seperators in the relative location of the main file. Then all files from that directory are collected and parsed again like the previous steps explained.

Checking AST

A new checker is created:

import v.checker

mut checker := checker.new_checker(table, &pref)

After checking your files in checker.errors and checker.warnings you can see the results.

Check ast.File

checker.check(parsed_file)

Check a list of ast.File

checker.check_files(parsed_files)

Generate target from AST

Generating C code works just as this:

import v.gen.c

res := c.gen(parsed_files, table, &pref)