Allow any character to be escaped

LANGUAGE.md

@@ -100,7 +100,7 @@ If an unescaped `~`, `~?` or `#` appears in the line, the associated operator is
     not tagged
 ```
 
-* regular text, i.e. any line that doesn't start with a special line type caracter: write some text into the [event buffer](#event-buffer). Support [text interpolation](#text-interpolation). Support [escape codes](#escape-codes). Don't accept children lines.
+* regular text, i.e. any line that doesn't start with a special line type character: write some text into the [event buffer](#event-buffer). Support [text interpolation](#text-interpolation). Support [escape codes](#escape-codes). Don't accept children lines.
 
 ```
 Hello,
@@ -522,14 +522,14 @@ Text
 
 By default, some processing is done on the event buffer before sending it to your game. You can disable these by disabling the associated features flages using `vm:disable` (see #api-reference).
 
-* strip trailing spaces: will remove any space caracters at the end of the text (for text event), or at the end of each choice (for choice event).
+* strip trailing spaces: will remove any space characters at the end of the text (for text event), or at the end of each choice (for choice event).
 
 ```
 (There is a space between the text and the tag expression that would be included in the text event otherwise.)
 Some text # tag
 ```
 
-* strip duplicate spaces: will remove any duplicated space caracters between each element that constitute the text (for text event), or for each choice (for choice event).
+* strip duplicate spaces: will remove any duplicated space characters between each element that constitute the text (for text event), or for each choice (for choice event).
 
 ```
 (There is a space between the text and the tag expression; but there is a space as well after the text interpolation in the last line. The two spaces are converted into a single space (the space will belong to the first text element, i.e. the "text " element).)
@@ -543,7 +543,7 @@ TODO: check if spacing rules are language-specific and move this to language fil
 
 ### Identifiers
 
-Valid identifiers must be at least 1 caracters long and can contain anything except the caracters ``~`^+-=<>/[]*{}|\_!?,;:()"@&$#%`` (that is, every special caracter on a US keyboard except '). They can contain spaces. They can not start with a number.
+Valid identifiers must be at least 1 characters long and can contain anything except the characters ``~`^+-=<>/[]*{}|\_!?,;:()"@&$#%`` (that is, every special character on a US keyboard except '). They can contain spaces. They can not start with a number.
 
 When defining an identifier (using a function, checkpoint or variable delcaration line), it will be defined into the current namespace (defined by the parent function/checkpoint). When evaluating an expression, Anselme will look for variables into the current line's namespace, then go up a level if it isn't found, and so on. Note that the namespace of functions with arguments are not accessible from outside the function.
 
@@ -665,23 +665,15 @@ How conservions are handled from Lua to Anselme:
 
 #### Escape codes
 
-These can be used to represent some caracters in string and other text elements that would otherwise be difficult to express due to conflicts with Anselme syntax.
+These can be used to represent some character in string and other text elements that would otherwise be difficult to express due to conflicts with Anselme syntax; for example to avoid a character at the start of a text line to be interpreted as another line type.
 
-* `\\` for `\`
-* `\"` for `"`
 * `\n` for a newline
 * `\t` for a tabulation
-* `\{` and `\}` for `{` and `}`
+* `\\` for `\`
-* `\[` and `\]` for `[` and `]`
+* `\"` for `"` to escape string delimiters
-* `\~` for `~`
+* `\{` and `\}` for `{` and `}` to escape text interpolation
-* `\#` for `#`
+* `\[` and `\]` for `[` and `]` to escape subtexts
-* `\$` for `$`
+* and, in general, for any character X we can get it by prefixing it with an `\`: `\X` for `X`
-* `\(` for `(`
-* `\>` for `>`
-* `\%` for `%`
-* `\§` for `§`
-* `\@` for `@`
-* `\:` for `:`
 
 #### Truethness
 

parser/common.lua

@@ -53,31 +53,12 @@ common = {
 		"{}"
 	},
 	-- escapement code and their value in strings
+	-- only includes the "special" escape codes, as the generic \. -> . is handled by default in parse_text
 	-- I don't think there's a point in supporting form feed, carriage return, and other printer and terminal related codes
 	string_escapes = {
-		-- usual escape codes
 		["\\\\"] = "\\",
-		["\\\""] = "\"",
 		["\\n"] = "\n",
 		["\\t"] = "\t",
-		-- string interpolation
-		["\\{"] = "{",
-		["\\}"] = "}",
-		-- subtext
-		["\\["] = "[",
-		["\\]"] = "]",
-		-- end of text line expressions
-		["\\~"] = "~",
-		["\\#"] = "#",
-		-- decorators
-		["\\$"] = "$",
-		-- line types
-		["\\("] = "(",
-		["\\>"] = ">",
-		["\\%"] = "%",
-		["\\§"] = "§",
-		["\\@"] = "@",
-		["\\:"] = ":",
 	},
 	-- list of possible injections and their associated name in vm.state.inject
 	injections = {
@@ -192,7 +173,9 @@ common = {
 					r = r2
 				end
 				-- replace escape codes
-				local escaped = t:gsub("\\.", common.string_escapes)
+				local escaped = t:gsub("\\.", function(escape)
+					return common.string_escapes[escape] or escape:match("^\\(.)$")
+				end)
 				table.insert(l, escaped)
 			end
 			-- expr

test/tests/string escaping.ans

@@ -5,3 +5,5 @@ quote {"\""}
 other codes {"\n"} {"\\"} {"\t"} \{braces}
 
 {"escaping expressions {"a"+"bc"} and \{stuff} \\ and quotes \""}
+
+generic symbol {"\£"}

test/tests/string escaping.lua

@@ -1,70 +1,91 @@
 local _={}
-_[25]={}
+_[39]={}
-_[24]={}
+_[38]={}
-_[23]={}
+_[37]={}
-_[22]={}
+_[36]={}
-_[21]={text="escaping expressions abc and {stuff} \\ and quotes \"",tags=_[25]}
+_[35]={}
-_[20]={text=" {braces}",tags=_[24]}
+_[34]={}
-_[19]={text="\9",tags=_[24]}
+_[33]={}
-_[18]={text=" ",tags=_[24]}
+_[32]={}
-_[17]={text="\\",tags=_[24]}
+_[31]={}
-_[16]={text=" ",tags=_[24]}
+_[30]={}
-_[15]={text="\n",tags=_[24]}
+_[29]={}
-_[14]={text="other codes ",tags=_[24]}
+_[28]={}
-_[13]={text="\"",tags=_[23]}
+_[27]={}
-_[12]={text="quote ",tags=_[23]}
+_[26]={}
-_[11]={text="a",tags=_[22]}
+_[25]={tags=_[39],text="\194\163"}
-_[10]={text="expression ",tags=_[22]}
+_[24]={tags=_[38],text="generic symbol "}
-_[9]={_[21]}
+_[23]={tags=_[37],text="escaping expressions abc and {stuff} \\ and quotes \""}
-_[8]={_[14],_[15],_[16],_[17],_[18],_[19],_[20]}
+_[22]={tags=_[36],text=" {braces}"}
+_[21]={tags=_[35],text="\9"}
+_[20]={tags=_[34],text=" "}
+_[19]={tags=_[33],text="\\"}
+_[18]={tags=_[32],text=" "}
+_[17]={tags=_[31],text="\n"}
+_[16]={tags=_[30],text="other codes "}
+_[15]={tags=_[29],text="\""}
+_[14]={tags=_[28],text="quote "}
+_[13]={tags=_[27],text="a"}
+_[12]={tags=_[26],text="expression "}
+_[11]={_[24],_[25]}
+_[10]={_[23]}
+_[9]={_[16],_[17],_[18],_[19],_[20],_[21],_[22]}
+_[8]={_[14],_[15]}
 _[7]={_[12],_[13]}
-_[6]={_[10],_[11]}
+_[6]={"return"}
-_[5]={"return"}
+_[5]={"text",_[11]}
-_[4]={"text",_[9]}
+_[4]={"text",_[10]}
-_[3]={"text",_[8]}
+_[3]={"text",_[9]}
-_[2]={"text",_[7]}
+_[2]={"text",_[8]}
-_[1]={"text",_[6]}
+_[1]={"text",_[7]}
-return {_[1],_[2],_[3],_[4],_[5]}
+return {_[1],_[2],_[3],_[4],_[5],_[6]}
 --[[
 { "text", { {
-      tags = <1>{},
+      tags = {},
       text = "expression "
     }, {
-      tags = <table 1>,
+      tags = {},
       text = "a"
     } } }
 { "text", { {
-      tags = <1>{},
+      tags = {},
       text = "quote "
     }, {
-      tags = <table 1>,
+      tags = {},
       text = '"'
     } } }
 { "text", { {
-      tags = <1>{},
+      tags = {},
       text = "other codes "
     }, {
-      tags = <table 1>,
+      tags = {},
       text = "\n"
     }, {
-      tags = <table 1>,
+      tags = {},
       text = " "
     }, {
-      tags = <table 1>,
+      tags = {},
       text = "\\"
     }, {
-      tags = <table 1>,
+      tags = {},
       text = " "
     }, {
-      tags = <table 1>,
+      tags = {},
       text = "\t"
     }, {
-      tags = <table 1>,
+      tags = {},
       text = " {braces}"
     } } }
 { "text", { {
       tags = {},
       text = 'escaping expressions abc and {stuff} \\ and quotes "'
     } } }
+{ "text", { {
+      tags = {},
+      text = "generic symbol "
+    }, {
+      tags = {},
+      text = "£"
+    } } }
 { "return" }
 ]]--

test/tests/text escaping.ans

@@ -7,3 +7,5 @@ other codes \n \\ \t
 decorators \# tag \~ condition \$ fn
 
 sub \[text]
+
+generic symbol \£

test/tests/text escaping.lua

@@ -1,26 +1,30 @@
 local _={}
+_[25]={}
+_[24]={}
+_[23]={}
+_[22]={}
 _[21]={}
 _[20]={}
-_[19]={}
+_[19]={tags=_[25],text="generic symbol \194\163"}
-_[18]={}
+_[18]={tags=_[24],text="sub [text]"}
-_[17]={}
+_[17]={tags=_[23],text="decorators # tag ~ condition $ fn"}
-_[16]={text="sub [text]",tags=_[21]}
+_[16]={tags=_[22],text="other codes \n \\ \9"}
-_[15]={text="decorators # tag ~ condition $ fn",tags=_[20]}
+_[15]={tags=_[21],text="quote \""}
-_[14]={text="other codes \n \\ \9",tags=_[19]}
+_[14]={tags=_[20],text="expression {a}"}
-_[13]={text="quote \"",tags=_[18]}
+_[13]={_[19]}
-_[12]={text="expression {a}",tags=_[17]}
+_[12]={_[18]}
-_[11]={_[16]}
+_[11]={_[17]}
-_[10]={_[15]}
+_[10]={_[16]}
-_[9]={_[14]}
+_[9]={_[15]}
-_[8]={_[13]}
+_[8]={_[14]}
-_[7]={_[12]}
+_[7]={"return"}
-_[6]={"return"}
+_[6]={"text",_[13]}
-_[5]={"text",_[11]}
+_[5]={"text",_[12]}
-_[4]={"text",_[10]}
+_[4]={"text",_[11]}
-_[3]={"text",_[9]}
+_[3]={"text",_[10]}
-_[2]={"text",_[8]}
+_[2]={"text",_[9]}
-_[1]={"text",_[7]}
+_[1]={"text",_[8]}
-return {_[1],_[2],_[3],_[4],_[5],_[6]}
+return {_[1],_[2],_[3],_[4],_[5],_[6],_[7]}
 --[[
 { "text", { {
       tags = {},
@@ -42,5 +46,9 @@ return {_[1],_[2],_[3],_[4],_[5],_[6]}
       tags = {},
       text = "sub [text]"
     } } }
+{ "text", { {
+      tags = {},
+      text = "generic symbol £"
+    } } }
 { "return" }
 ]]--